Conservation
and
utilization of sweetpotato genetic
diversity in Asia
Proceedings of 2nd Asian Network for
Sweetpotato Genetic Resources
3–5 November 1999, Bogor, Indonesia
V. Ramanatha Rao and Michael Hermann (editors)
Conservation
and
utilization of sweetpotato genetic
diversity in Asia
Proceedings of 2nd Asian Network for
Sweetpotato Genetic Resources,
Proceedings
of training course
cumBogor,
workshop Indonesia
3–5 November
1999,
10–17 May 1998, Kunming and Xishuangbanna, Yunnan, China
V. Ramanatha Rao and Michael Hermann (editors)
Hosted by:
International Potato Center (CIP), Regional for East,
Southeast Asia and the Pacific (ESEAP)
Kebun Percabaan Muara
Jl. Raya Ciapus, Bogar 16610
Indonesia
Sponsored by:
International Plant Genetic Resources Institute (IPGRI)
IPGRI is an institute of
the Consultative Group
on International
Agricultural Research
(CGIAR)
II
The International Plant Genetic Resources Institute (IPGRI) is an autonomous international
scientific organization, supported by the Consultative Group on International Agricultural
Research (CGIAR). IPGRI’s mandate is to advance the conservation and use of genetic
diversity for the well-being of present and future generations. IPGRI’s headquarters is based
in Rome, Italy, with offices in another 19 countries worldwide. It operates through three
programmes: (1) the Plant Genetic Resources Programme, (2) the CGIAR Genetic Resources
Support Programme, and (3) the International Network for the Improvement of Banana
and Plantain (INIBAP).
The international status of IPGRI is conferred under an Establishment Agreement which,
by January 2000, had been signed and ratified by the Governments of Algeria, Australia,
Belgium, Benin, Bolivia, Brazil, Burkina Faso, Cameroon, Chile, China, Congo, Costa Rica,
Côte d’Ivoire, Cyprus, Czech Republic, Denmark, Ecuador, Egypt, Greece, Guinea, Hungary,
India, Indonesia, Iran, Israel, Italy, Jordan, Kenya, Malaysia, Mauritania, Morocco, Norway,
Pakistan, Panama, Peru, Poland, Portugal, Romania, Russia, Senegal, Slovakia, Sudan,
Switzerland, Syria, Tunisia, Turkey, Uganda and Ukraine.
Financial support for the Research Agenda of IPGRI is provided by the Governments
of Australia, Austria, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, F.R. Yugoslavia (Serbia and Montenegro), Finland, France,
Germany, Greece, Hungary, Iceland, India, Ireland, Israel, Italy, Japan, Republic of Korea, Latvia,
Lithuania, Luxembourg, Macedonia (F.Y.R.), Malta, Mexico, the Netherlands, Norway, Peru,
the Philippines, Poland, Portugal, Romania, Slovakia, Slovenia, South Africa, Spain, Sweden,
Switzerland, Turkey, the UK, the USA and by the Asian Development Bank, Common Fund
for Commodities, Technical Centre for Agricultural and Rural Cooperation (CTA), European
Environment Agency (EEA), European Union, Food and Agriculture Organization of the United
Nations (FAO), International Development Research Centre (IDRC), International Fund for
Agricultural Development (IFAD), Interamerican Development Bank, Natural Resources
Institute (NRI), Centre de coopération internationale en recherché agronomique pour le
développement (CIRAD), Nordic Genebank, Rockefeller Foundation, United Nations
Development Programme (UNDP), United Nations Environment Programme (UNEP), Taiwan
Banana Research Institute (TBRI) and the World Bank.
The geographical designations employed and the presentation of material in this publication
do not imply the expression of any opinion whatsoever on the part of IPGRI or the CGIAR
concerning the legal status of any country, territory, city or area or its authorities, or concerning
the delimitation of its frontiers or boundaries. Similarly, the views expressed are those of
the authors and do not necessarily reflect the views of these participating organizations.
Citation: Ramanatha Rao and Michael Hermann, editors. 2001. Conservation and Utilization
of Sweetpotato Genetic Diversity in Asia - Proceedings of the Asian Network for Sweetpotato
Genetic Resources Workshop, 3-5 November 1999, Bogor, Indonesia. IPGRI-APO, Serdang,
Malaysia
ISBN 92-9043-467-8
IPGRI Regional Office for Asia, the Pacific and Oceania
UPM Campus, Serdang, 43400 Selangor Darul Ehsan, Malaysia
© International Plant Genetic Resources Institute, 2001
III
Contents
Foreword
v
The ANSWER Network: a CIP Statement
Gordon Prain
1
Summary of the Proceedings
Michael Hermann
3
Sweetpotato Germplasm Conservation and Breeding in the
Department of Agriculture, Sri Lanka
P.S.A.D. Premathilake
6
Sweetpotato Germplasm Conservation Activities in Universiti
Putra Malaysia, Malaysia
M.S. Saad
9
In Vitro Conservation of Sweetpotato Germplasm
Guo Xiaoding, Zhou Ming-De and Wang Yi
16
Present Status of Sweetpotato Germplasm Conservation in Indonesia
M. Jusuf, St.A.Rahayuningsih and Minantiyorini
25
Conservation and Documentation of Sweetpotato Genetic Resources
in Irian Jaya
Ery Atmojo
34
Sweetpotato Germplasm Conservation and Breeding in CIP-ESEAP
Tjintokohadi, N.L. Ningsih and Il Gin Mok
39
Recent Progress on the Conservation and Use of Sweetpotato
in the Philippines
Algerico M. Mariscal, Jose L. Bacusmo, Villaluz Z. Acedo and Enrique Abogadie
47
Conservation and Use of Sweetpotato in Thailand
Narin Poolperm
53
Status of Conservation and Use of Sweetpotato Germplasm in Vietnam
Luu Ngoc Trinh, Bui Tuyet Mai and Nguyen Ngoc Hue
58
Recent Progress in the Conservation and Use of Sweetpotato
Germplasm in India
S.K. Naskar, C.S. Easwari Amma and S.G. Nair
63
Appendix 1. Programme
68
Appendix 2. List of Participants
70
Appendix 3. Summary Tables from Group Discussions
72
V
Foreword
Sweetpotato is a post-Colombian introduction into Asia. However, over years of cultivation
in varied agroclimatic conditions of the vast region, significant genetic diversity is now
available and the need for collecting, conserving and using this diversity was recognized
around 1993–94. A dialogue between the International Centre for Potato (CIP) and the
International Plant Genetic Resources Institute (IPGRI) on enhancing collaboration among
the sweetpotato workers in Asia was initiated at the end of 1993. During 1994–95, a draft
concept paper on “collaboration for the conservation of sweetpotato biodiversity in Asia
and the Pacific” was prepared jointly by Dr Schmiediche of CIP-Bogor and Dr Ramanatha
Rao of IPGRI-APO. This was circulated within CIP and IPGRI. Based on the comments
received, the concept note was finalized in 1995–96. It attracted much attention from a number
of countries in the region. This led to the organization of a joint meeting with CIP in Bogor,
Indonesia, in May 1996 which led to the formation of the Asia Network on Sweetpotato
Genetic Resources (ANSWER) with 11 partner countries. The proceedings of the meeting
were published by IPGRI and were widely disseminated. Initially it was agreed that IPGRIAPO would provide secretariat assistance to ANSWER.
During 1996–1999, several activities were undertaken by partners under the auspices
of ANSWER, supported by CIP, IPGRI and the Government of Japan. Such activities
included genetic diversity research, training on maintenance, characterization and
duplicate identification and rationalization of collections in field genebanks.
Changes to ANSWER in 1999
Members of the ANSWER network (except those from Japan and PNG) met in Bogor along
with CIP and IPGRI representatives on November 2–5, 1999, in order to discuss the further
development of the network. The objectives of this meeting were mainly to review progress
in sweetpotato germplasm conservation since last meeting; identify priority problems and
develop a plan for a regional project, with emphasis on coordinated actions and shared
resources; define project outputs, responsibilities and funding needs and define governance
and management of ANSWER activities. The proceedings that have been put together jointly
by CIP and IPGRI indicate that much has been achieved on the objectives set for the meeting.
An important outcome of the meeting is the agreement on the role of CIP in the governance
of the Network which would lead to its increased role in conservation and use of sweetpotato
germplsm in Asia and that of IPGRI which will continue to provide technical and scientific
backstopping to ANSWER. This collaboration represents a good model for inter-CGIAR
Centre collaboration together with national partners in utilizing existing resources to meet
identified needs for plant genetic resources of a particular crop in the region.
These proceedings have been compiled and edited based on the papers presented
at this workshop, dealing with objectives as set by ANSWER members. They contain
the information on the progress made during the three years since the members met
last time, but more importantly they record the commitments made by different partners
for furthering sweetpotato genetic resources work in Asia. They also contain the
recommendations on strategies and approaches proposed at the workshop, which will
form the basis for future work of ANSWER. It is my hope that the publication and
distribution of this volume will stimulate further the already vigorous activity in
sweetpotato genetic resources conservation and use in the region.
Percy Sajise
Regional Director
IPGRI Office for Asia, Pacific and Oceania
1
The ANSWER Network: a CIP Statement
Gordon Prain
CIP, ESEAP regional representative (currently project leader, SIUPA, System-wide
Initiative for Urban and Peri-urban Agriculture)
Since the founding meeting of ANSWER in 1996 there has been a growing interest in
the issue of conserving sweetpotato genetic resources in the region. This has partly
been stimulated by a general growth in interest at the international level in crop genetic
resources and has increased the visibility and coherence of the CGIAR’s approach
through the System-wide Genetic Resources Program and SINGER, co-ordinated by
IPGRI. But it has also been the result of several activities concerned specifically with
improving the representativeness and efficiency of ex situ conservation of sweetpotato,
understanding better the characteristics of sweetpotato diversity in genebanks and in
farmers’ fields and exploring the potential uses of collected material through better
evaluation.
Examples of these activities include the meeting in the Philippines in early 1997
sponsored by the Japanese Government, which explored recent experiences in
sweetpotato genetic conservation and breeding and examined the feasibility of
developing action plans for future collaborative work (Prain 1998). A follow-up to that
meeting was the training course jointly organized by IPGRI and CIP in September 1997
to share approaches and methods to conservation and documentation among specialists
in the region. At the same time, CIP spearheaded a regional documentation of
sweetpotato genebanks as part of the broader IPGRI-SINGER.
In Indonesia, the period from 1997 up to the present has seen an intensive effort
to improve documentation methods for ex situ conservation (Jusuf et al. 1998). This work
has led to the production of a CD-ROM of Indonesian sweetpotato (Prain and Hermann
2001), which it is hoped will be a model for documentation of other genebanks within
the network. Inter-institutional and interdisciplinary teams in Indonesia and the
Philippines have also been assessing in situ conservation during this period with results,
which may be valuable for other countries (Prain and Bagalanon 1998;Yaku and
Widyastuti1998; Prain and Campilan 1999; Prain et al. 2000). Increased interest has also
been evident in China to step up collection efforts in areas underrepresented in the
germplasm collections in Xuzhou. In early 1998 genetic resources specialists in Vietnam
joined an IPGRI-coordinated global project on in situ conservation of crop genetic
diversity and have begun to develop considerable skills and experience in this field
in the following two years. Though sweetpotato is not one of the targeted crops in the
in situ project, taro is included and the Vietnamese specialists involved also have
responsibility for sweetpotato. There are thus very good opportunities for transferring
the experiences with taro to sweetpotato conservation in Vietnam and hopefully, to
the entire Asian region.
These activities have so far been mainly the result of independent initiatives by
national systems, CIP, IPGRI and the Japanese Government rather than outputs of the
ANSWER network. Lack of funds has undoubtedly limited the extent to which the
networking aims of the 1996 meeting could have been met. Attempts to remedy that
situation began in 1998 when a new draft proposal for the continuation of the ANSWER
network was prepared and shared amongst ANSWER members. There may also have
been some lack of clarity from the first meeting about alternative options for the network,
given variable availability of resources.
2
CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
The Second ANSWER meeting reported here has been important for two main
reasons. The papers presented at the meeting and now collected in this volume are
excellent testimony to the growing interest and capacity in the region for sweetpotato
genetic resources research referred to at the beginning of this statement. Second, the
meeting gave particular attention to the issue of flexible response to different levels
of available resources. This has meant that a programme of action was determined and
has already been implemented. In particular, an ANSWER website has been established
(http://www.eseap.cipotato.org/ANSWER/index.htm) and first steps to pool databases
have been undertaken.
In closing I would like to pay tribute to the dedication of the genetic resources
specialists from ANSWER member countries and to the way in which, through the
several meetings which have taken place since its inauguration, you are fast developing
into a collaborative genetic resources partnership. I would also like to thank IPGRI,
through Dr Ramanatha Rao, for the extremely important support they have continued
to give ANSWER during the past three years. The support to the sweetpotato genetic
resources training course, the ANSWER review meeting reported here and the
publication of these Proceedings are an important example of another partnership:
international genetic resources collaboration between CIP as a commodity centre and
IPGRI, in support of national crop conservation efforts.
References
Jusuf, M., St.A. Rahayuningsih, Minantyorini, and I.G. Mok. 1998. Sweetpotato breeding
and conservation in Indonesia. Pp. 49–62 in Sweetpotato Genetic Resources
Conservation and Use in Asia, Proceedings of MAFF-PRCETC International
Workshop (R.L. Tatala-Sanico, ed.) MAFF, Tsukuba, Japan.
Mok, I.G. and P. Schmiediche. 1999. Collecting, characterizing and maintaining sweetpotato
germplasm in Indonesia. Plant Genetic Resources Newsletter 118:12-18.
Prain, G.1998. The potential for on-farm conservation of rootcrop germplasm in the
Philippines. Pp.11–36 in Sweetpotato Genetic Resources – Conservation and Use
in Asia (R.L. Tatala-Sanico, ed.). MAFF/PRCRTC, Philippines.
Prain, G. and C.P. Bagalanon. 1998. Conservation and Change: Farmer Management
of Agricultural Biodiversity in the Context of Development. UPWARD, Laguna.
Prain, G. and D. Campilan. 1999. Farmer Maintenance of Sweetpotato Diversity in Asia:
Dominant Cultivars and Implications for In Situ Conservation. Impact on a Changing
World, CIP, Peru.
Prain, G. and M. Hermann (eds.). 2001. A Guide to Indonesian Sweetpotato Diversity.
CD-ROM, CIP, ANSWER.
Prain, G., J. Schneider and C. Widiyastuti. 2000. Farmer’s maintenance of sweetpotato
diversity in Irian Jaya. Pp. 54–59 in Encouraging Diversity – The Conservation and
Development of Plant Genetic Resources, (Almekinders Conny and De Boef Walter,
eds.). Intermediate Technology, London.
Yaku, A. and C. Widyastuti. 1998. Tapping sweetpotato and taro genetic resources for
sustainable livelihood in Irian Jaya. Pp.73–80 in Sustainable Livelihood for Rural
Households: Contributions from Rootcrop Agriculture (UPWARD, ed.). UPWARD,
Philippines.
3
Summary of the Proceedings
Michael Hermann
CIP
Members of the ANSWER network (Asian Network for Sweetpotato Genetic Resources)
from China, India, Indonesia, Malaysia, Philippines, Sri Lanka, Thailand and Vietnam,
met in Bogor along with CIP and IPGRI representatives, on 2–5 November 1999, in
order to discuss the further development of the network. Members from Japan and
Papua New Guinea could not attend.
Objectives
•
•
•
•
•
•
•
•
•
The meeting had the following objectives:
Review progress in sweetpotato germplasm conservation by ANSWER participants
since last meeting
Take stock of sweetpotato holdings in the region and develop a plan for ANSWER
database
Identify priority problems of sweetpotato conservation in the ANSWER region
Develop a plan for a regional sweetpotato conservation project, with emphasis on
coordinated actions and shared resources
Define project outputs, responsibilities and funding requirements
Define priorities for funding proposal development
Define governance and management of ANSWER activities
Further consider the possibility of sweetpotato conservation through botanical seeds.
Dr M. Jusuf, ANSWER chairman, opened the meeting in the morning of November
3, and Dr Gordon Prain (CIP) and Dr Ramanatha Rao (IPGRI) delivered welcome
addresses. The rest of the first day was reserved for presentations of member scientists
(see appended programme). This was a valuable exercise to bring participants up to
date with each other ’s progress and to set the stage for the following two days’
deliberations.
Problem identification and prioritization
On the second and third day, we used elements of the Participatory Project Planning
methodology, particularly the “card method”. Participants wrote down ideas and concepts
on cards, which were pinned on a wall, discussed, reformulated, rearranged and so forth.
The first exercise was to identify problems in relation to sweetpotato germplasm
conservation in Asia. This provided a good sense for the scope of persisting problems,
which were grouped into larger thematic areas. The following groups emerged:
• Lack of, or inadequate, conservation strategies (cost reduction, priority material,
guideline development)
• Clonal duplicates
• Lack of funding (donor fatigue, lack of commitment, etc.)
• Inadequate information and germplasm exchange
• Insufficient public awareness
• Insufficient database management (coordination, standards, gaps, fragmentation of
efforts)
• Geographical and other gaps in collections
• Size of collections (core approach)
4
•
•
•
CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Insufficient germplasm utilization (impact)
Management problems (various)
Maintenance of problematic material (poorly adapted, late maturing, non-flowering,
non-tuberizing).
The participants then split into two groups, each dealing with a subset of these
problem areas and charged with the development of a matrix, which would restate
the problems and find complementary outputs and activities for project implementation.
The purpose of this exercise was to identify priorities for action of a regional sweetpotato
conservation project emphasizing coordination between members and shared resources.
The following areas (or components) of future ANSWER projects were identified (in
order of priority):
• Strengthening the network
• Information and germplasm exchange
• Training
• Increased germplasm utilization
• Impact studies
• Complementary conservation (seeds, in situ)
• Characterization
• Regional sweetpotato genebank (back-up facility).
Since ANSWER lacked an appropriate level of activities in its previous phase, except
for some activities in Malaysia and the Philippines supported by IPGRI, and given the
uncertainty of fund-raising, the group agreed that it should give thought to activities
that could be implemented immediately. Ideally, such activities would not require large
amounts of external funding, but would provide ANSWER with coherence and better
visibility.
The following activities were identified as priorities for action with little or no
external funding:
1. It was agreed to establish an ANSWER web page on the CIP-Bogor server. Mr
Sukendra Mahalaya, CIP information management officer, in consultation with the
newly elected ANSWER Coordinator is expected to implement the web page not
much later than December 1999.
2. Inventory germplasm related information of ANSWER members and document in
appropriate form. Establish minimum data sets for an ANSWER germplasm
database, the first version of which should become available by the end of 2000
and be linked to the ANSWER web page. Ideally, this database should allow for
queries, perhaps using the tool kits offered by SINGER. Initially, the database should
make available passport data (allowing mapping) but later also characterization
data. Prof Gerry Mariscal (Philippines), Mr Tjintokohadi (CIP, ESEAP) and Dr
Michael Hermann (CIP, Lima) were requested to team up as a task force to implement
this. CIP agreed to provide a clearing-house mechanism for database consolidation
and the definition of data standards.
3. IPGRI agreed to assist ANSWER with the translation of sweetpotato research material
in Chinese, such as the ones on in vitro technology and “artificial seed”, which was
of great interest to the members.
4. Dr Ramanatha Rao (IPGRI) also agreed to take the initiative with the publication
of the proceedings of the meeting. He raised the possibility that, funds permitting,
IPGRI might contribute to that publication in 2000.
Dr Michael Hermann (CIP, Lima) committed to take the initiative with proposal
development for external funding of ANSWER. The group felt that it would be most
appropriate to seek incremental funding from different donors (e.g. foundations) for
5
components of the ANSWER agenda. That mode would hopefully allow for diversified
investment in ANSWER and ensure focus on priorities while attenuating emphasis of
the network character of activities, which “fatigued” donors do not view too favourably.
Dr Hermann will get back to the ANSWER Coordinator and members with drafts for
their comments.
Governance
The group then deliberated about governance and membership of ANSWER. While
recognizing that ANSWER came into being as an unanticipated result of the 1996
meeting, by the initiative of very active members, and that it needed to maintain a
good deal of informality, it was felt that membership needed to be “regulated”. Also
to make sure that there would be more interaction between members, an ANSWER
Coordinator needed to be appointed. ANSWER’s network character was reaffirmed as
opposed to a project mode.
First, the group confirmed the terms of reference for the newly created ANSWER
Coordinator:
• Appointed among ANSWER members by election for a minimum period of two
years
• Can be re-elected during ANSWER meetings
• Coordinate activities of ANSWER drawing on support from the ANSWER Secretariat
• Organize a bi-yearly meeting
• Appoint task forces among the members as needed
• Report activities and financial issues during network meetings.
Upon request by the members and IPGRI, CIP agreed to serve as ANSWER secretariat
and to provide modest financial support for communications by the ANSWER
Coordinator. It was agreed that IPGRI would continue to provide technical and
networking support, and would be a member and advisor to ANSWER.
The following requirements for ANSWER membership were endorsed:
• Individuals or institutions directly involved in sweetpotato germplasm conservation
and utilization
• Represent an Asian country where sweetpotato is an important crop or is recognized
as a priority crop by the government (for production or R&D)
• Relevant individuals need to be designated by their institutions
• Multiple membership (sweetpotato institutions) per country possible, but as far as
possible, should be avoided as members might be required to play representational
role
• Members who are not, or no longer, actively involved in sweetpotato germplasm
conservation should not be appointed as their institutions’ representatives or resign
from the task.
CIP and IPGRI will be non-voting members of ANSWER.
Finally, Prof Algerico Mariscal, from the Philippine Rootcrop Research and Training
Centre (PRCRTC), accepted the unanimous nomination to serve as the future ANSWER
Coordinator. The meeting closed on a vote of thanks to Dr M. Jusuf, RILET, Indonesia,
the outgoing chairman, who has successfully steered the network through its first three
years.
6
CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Sweetpotato Germplasm Conservation and Breeding in the
Department of Agriculture, Sri Lanka
P.S.A.D. Premathilake
Horticultural Crop Research Institute, Gannoruwa, Peradeniya, Sri Lanka
Introduction
Sweetpotato is a crop of exotic origin, but people regard it as indigenous since it has
been in cultivation in Sri Lanka as an important traditional food crop from very ancient
times. It was an integral part of the poor man’s crop in subsistence farming, now on
its way to become a market-oriented crop. In Sri Lanka, sweetpotato can be cultivated
throughout the year in different growing situations (rice fallow, land, open highland,
river valley basin, homestead, partial shade) in all agroecological zones (De Silva and
Premathilake 1985).
The present annual extent under sweetpotato is 9040 hectares and annual production
is 85 882 metric tones. In 1996, the average yield was 6.6 t/ha and at present it is 9.5 t/ha.
It is estimated that per capita availability of sweetpotato is 4.3 kg/yr.
Germplasm collection
The sweetpotato genetic resources in the country are diverse. Genetic materials collected
to build up a germplasm bank include local varieties, introductions and breeding lines.
However, with the natural calamities some of the genetic resources became extinct or
missing. The Department of Agriculture (DOA) has collected and maintained
sweetpotato genetic resources in the field genebank and in the laboratory in the form
of tissue culture. The Horticultural Crop Research Institute maintains the field genebank
and the Plant Genetic Resources Centre maintains in vitro collection.
Crop improvement programme
The general objective of the crop improvement programme is to produce varieties having
characters desired by user groups. The specific objectives are high yield, high dry matter
content, low sugar content, short crop duration, good eating quality and acceptable
post harvest losses.
The basic step in any crop improvement programme is to create genetic variability.
In sweetpotato, genetic variability is created through conventional methods and nonconventional methods. The conventional methods are collecting of germplasm,
introductions, selective hybridization and polycross breeding.
DOA has recommended six (Wariyapola Red, CARI-9, CARI-273, CARI-426,
Ranabima and Wariyapola, a white high yielding 20–24 t/ha) sweetpotato varieties for
general cultivation and two varieties (Shanthi and Chithra) for low-lying situations
under wet zone (12–16 t/ha). As a result of combined superior genotypes existing in
the germplasm collection through selective hybridisation, CARI-9 and CARI-273 were
identified. As sweetpotato is an insect pollinated species, polycross breeding enhances
the genetic variability for faster crop improvement by minimizing the breeding problems
encountered with sweetpotato. The sweetpotato varieties, namely CARI-426 and
Ranabima, are creditable products of polycross breeding in sweetpotato. The Wariyapola
White is a creditable product of natural mutation and Wariyapola Red, Shanthi and
Chithra are natural selections from the native germplasm collection.
7
Improved sweetpotato varieties developed in Sri Lanka were not widely adopted
by farmers because they were generated based on the researchers’ criteria without
consideration of the end users’ needs. Yield, resistance and agronomic traits were
considered important by researchers while qualitative traits were considered as more
important by users. Therefore user participation in variety selection of sweetpotato was
started. This showed that users would readily adopt the new clones.
Current status
Genetic resources of sweetpotato from within and outside the country have been
collected to build up a germplasm bank. Now 135 accessions of sweetpotato, which
consist of 55 local clones, 39 introductions and 41 breeding lines, are maintained in
the field genebank. Evaluation of these genetic resources has revealed that there is a
broad variability in root yield, maturity, quality and agronomic characters. The Plant
Genetic Resources Centre (PGRC) is maintaining 85 accessions in vitro.
Sweetpotato can be grown throughout the year in Sri Lanka. But it is mainly grown
with the southwest (Yala) and northeast (Maha) monsoon rains. If irrigation water is
available it can be grown throughout the year. The germplasm accessions are replanted
twice a year in the field genebank. The accessions are planted in mounds 90c.m apart
having 5 stem cuttings per mound. Losses are observed in the field genebank through
continuous replanting.
Current number of accessions with passport data, morphological
characterization and evaluation data
Recommended varieties, pre-released varieties and some local varieties have passport
data and morphological characterization data. These are kept in files and not in a
computerised database. Evaluation data are available for recommended varieties and
pre-released varieties.
Number of accessions with farmers’ knowledge
Most farmers grow the local recommended sweetpotato variety Wariyapola Red. The
farmers know the local varieties and the recommended varieties. Non-availability of
planting material of recommended varieties is a problem for the spread of the varieties.
Establishment of large-scale cultivation of improved varieties on farmers’ fields and
government farms can overcome this constraint.
Establishment of a germplasm collection
There are many reasons for the establishment of a germplasm collection. In many cases
a germplasm collection is needed for the crop improvement programme. Plant breeders
require genetically diverse material to develop improved crop varieties. The more diverse
the gene pool, the higher is the probability that it would contain desirable genes.
Germplasm collection is needed to conserve endangered species. Further it is needed
to conserve for future requirements.
8
CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Problems and constraints of field genebank management
Maintenance of vegetative materials in the field is vulnerable to many losses. Therefore,
field genebank management has the following problems:
• High cost of maintenance in terms of land, supplies and labour
• Biotic constraints (weevil/nematode/diseases, recycling of vines, decaying own and
other crop residues, inter- and intraspecies competition) and abiotic constraints
(excessive moisture, occasional drought, high temperature, soil acidity and alkalinity,
soil compaction and poor aeration)
• Duplicates continue to be maintained adding to cost
• Gradual loss of true-to-type germplasm due to mixtures between accessions in the
collection
• Lack of financial support.
Future plans
•
•
•
•
•
Characterization of all sweetpotato varieties
Removal of duplicates
Sharing of information related to field genebank management
Exchange of sweetpotato germplasm with other countries
Clean-up of material.
References
De Silva, K.P.U and A. Premathilake.1995. Screening of sweetpotato genotypes in ricefallow environments. Incorporation of users’ criteria in variety development of
sweetpotato. Selected Research Papers 1994/95wl. 2: Sweetpotato, 1-7. SAPPRAD,
Philippines.
De Silva, K.P.U and A. Premathilake.1988. Performance of promising sweetpotato lines,
CARI –426, developed through polycross breeding. Proceedings of the Sri Lanka
Association for Advancement of Science 44(1).
9
Sweetpotato Germplasm Conservation Activities in Universiti Putra
Malaysia, Malaysia
M.S. Saad
PGRC, Institute of Bioscience, UPM, Serdang, Malaysia
Introduction
Sweetpotato is planted in a rather small acreage in Malaysia. In 1998, the total area
planted with sweetpotato in Peninsular Malaysia was 2070 hectares (MOA 1999).
However, due its potential as a source of food, in 1995 the crop was listed in the priority
list of the Malaysian Intensified Research in Priority Areas programme. Since then several
institutions have started research and development programmes on sweetpotato. Among
them are the Malaysian Agricultural Research and Development Institute (MARDI),
the Department of Agriculture (DOA) and Universiti Putra Malaysia (UPM).
Sweetpotato R&D programme in UPM was started in 1983 at the UPM Sarawak
Campus. In 1987, the programme was moved to the Faculty of Agriculture, UPM main
campus in Serdang, Selangor, Malaysia. Sweetpotato germplasm conservation activity
at UPM has been going on since 1983. All the germplasm are now being kept at the
Plant Genetic Resources Centre (PGRC), UPM. This paper reports the current status
of the sweetpotato germplasm conservation in UPM.
Germplasm collection
Table 1 lists the sweetpotato germplasm being maintained at the PGRC. To date, the
total number of sweetpotato germplasm maintained at the PGRC is 217. The number
is much smaller as compared to the total number of germplasm collected or received.
Many of them were lost due to pest attack, especially virus and mycoplasma. However,
a few of them were identified as duplicates and discarded.
Table 1. The numbers and locations/sources of the
sweetpotato germplasm in Plant Genetic Resources Centre,
Universiti Putra Malaysia
Country/Source
Number of Accessions
Malaysia
132
Peninsular Malaysia
86
Sarawak
28
Sabah
18
Indonesia
Irian Jaya
Java
55
South America (CIP)
16
AVRDC
Philippines
Total
14
20
217
30
25
10 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
During 1983–1996, a total of 99 accessions were collected from five areas in Sabah
and Sarawak. In 1988, collecting was started in Peninsular Malaysia. To date, the total
number of accessions collected from Peninsular Malaysia is 151. The collection covers
almost all parts of Malaysia (Fig. 1).
Fig. 1 Map of Malaysia showing the sites of sweetpotato germplasm collection (black spots)
In 1988, a total of 20 sweetpotato accessions were obtained from AVRDC, Taiwan, and
in 1994 CIP sent 20 mostly South American accessions. In 1997, collaborative work was
started with IPGRI to study genetic variation of sweetpotato from different subregions
in Asia using molecular markers (RAPD and SSR). Through this collaboration,
sweetpotato germplasm have been obtained from Indonesia and Philippines. The
germplasm from Philippines were obtained through Visayas State College of Agriculture
(ViSCA).
Native cultivars and breeding lines
Table 2 presents the numbers of native cultivars and breeding lines within the
sweetpotato germplasm collected from within Malaysia. They comprise mostly native
cultivars that are being grown by farmers. Of the132 accessions from Malaysia, 67 were
actually collected from farmers’ fields. Most farmers prefer to grow their own cultivars.
The more advanced farmers select their own cultivars and share or sell the cuttings
to their friends and other farmers. Many farmers grow several cultivars on their farms.
The choice of cultivars grown by farmers depends very much on the market demand
at a particular time and areas. They normally grow cultivars that produce high yield
and those with special characters that capture higher price. Normally, the cultivars grown
by farmers from different areas are not similar. However, in Peninsular Malaysia, a
few of the very popular cultivars were found grown by several farmers in different
states.
11
Table 2. Numbers of native cultivars and breeding lines in PSGT sweetpotato germplasm from
Malaysia
Source
Total
Native Cultivars
Breeding Lines
Peninsular Malaysia
86
46 (53.5%)
13 (15.1%)
Sarawak
28
13 (46.4%)
1 (3.6%)
Sabah
18
8 (44.4%)
0 (0.0%)
Total
132
67 (50.8%)
14 (10.6%)
In 1995, a polycross breeding programme using 20 selected local germplasm was started.
Several potential breeding lines or clones have been isolated. To date, a total of 12
potential clones have been put into the list of our sweetpotato germplasm. These clones
were selected for high yield and hardiness. They are being subjected to further testing
and evaluation. Only two released varieties were included in our germplasm collection,
both released by MARDI, namely Bukit Naga and Gendut.
Method of conservation
All the sweetpotato germplasm were kept in a field genebank. For the purpose of
characterization and evaluation, they are planted in the field in rows and replicated
trials. At the same time, they are also planted in culvert rings (Fig. 2). Sweetpotato
can be maintained in culvert rings for a period of two years without replanting. In
addition, the area can be maintained easily, plants will not mix and they require less
space (Saad 1995). In 1998, an in vitro laboratory was set up to produce virus-free planting
materials and conserve germplasm in vitro. Initial work has started and a total of 30
accessions are now being tested for in vitro conservation.
Fig. 2 Planting sweetpotato germplasm in culverts. Spreading out vines are
trimmed and the surrounding areas can be easily kept clean.
12 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Passport data, characterization and agronomic evaluation
All sweetpotato accessions collected from Malaysia have complete passport data and
information on farmer knowledge is also available. However, those obtained from other
sources are without complete passport data (Table 3). Characterization has been done
on 213 of the accessions. Four new accessions were collected recently from Peninsular
Malaysia and they are now being planted in the field for characterization and evaluation.
Agronomic evaluation was done using both single row and replicated trials. Nutritional
characters (dry matter, protein and carbohydrates) were measured using the NIRS
machines (Saad 1996; Saad and Yunus 1996). Generally the characteristics of the
Malaysian sweetpotato are not much different from those from other countries (Saad
et al. 1999a; 1999b). However, there is wide variation in leaf and yield characters,
nutritional characters and plant types.
Table 3. Numbers of accessions with passport data, characterized and agronomically evaluated
Number of Accessions
Country/ Source
Total
Passport
Characterization
Agronomic
data
data
evaluation data
Malaysia
132
132
128
128
Indonesia
55
–
55
55
South America (CIP)
16
–
16
16
AVRDC
14
–
14
14
Philippines
20
–
–
–
Total
217
132
213
213
Molecular characterization
In 1997, PSGT and IPGRI started a collaborative effort to study sweetpotato genetic
diversity using RAPD and SSR molecular markers. DNA extraction has been completed
on 147 accessions. They are from Indonesia (53), Malaysia (60), South America (14) and
the Philippines (20) (Table 4). The samples from the Philippines have just arrived and
at the time of writing this report they were still in quarantine. PCR analysis has been
done on 84 of the samples.
Table 4. Countries of origin and numbers of sweetpotato accessions used in the RAPD analysis
Number of
DNA
PCR
Band
Country
Accessions
Extraction
Analysis
Analysis
Indonesia
53
Irian Jaya
28
20
10
Other Areas
25
20
–
Malaysia
60
Sabah
8
5
4
Sarawak
8
6
5
Kedah
8
5
1
Johor
6
–
–
Selangor
7
2
2
Terengganu
7
1
1
Kelantan
5
1
1
Pahang
6
5
1
Perak
5
5
1
South America
14
14
14
14
Total
127
127
84
40
13
As for the RAPD analysis, a total of 54 primers were tested and 19 of them were found
to show variation in banding pattern (Table 5). So far, RAPD analysis using 19 primers
has been completed for the South American samples. Analysis of the Indonesian samples
is almost 85% completed. However, only 50% of the samples from Malaysia have so
far been analyzed.
Work on SSR is still in the preliminary stage. We are testing primers from various
sources that might work for the samples.
Table 5. List of primers used in the RAPD
analysis in sweetpotato
Primer No.
Sequences (5’ – 3’)
OPG 2
GGCACTGAGG
OPG 3
GAGCCCTCCA
OPG 4
AGCGTGTCTG
OPG 5
CTGAGACGGA
OPG 6
GTGCCTAACC
OPG 8
TCACGTCCAC
OPG 9
CTGACGTCAC
OPG 13
CTCTCCGCCA
OPG 14
GGATGAGACC
OPA 5
AGGGGTCTTG
OPA 8
GTGACGTAGG
OPA 20
GTTGCGATCC
OPB 3
CATCCCCCTG
OPB 7
GGTGACGCAG
OPB 11
GTAGACCCGT
OPC 1
GGAGGGTGTT
OPC 10
TTCGAGCCAG
OPD 1
ACCGCGAAGG
OPD 6
ACCTGAACGG
The use of RAPD markers for duplicate detection
Six sweetpotato accessions from Malaysia that were identified as duplicates, namely
308-B, 309-B, 423-D, 428-D, 448-D and 451-C, were subjected to RAPD analysis. A total
of nine primers were used in the study. The results showed that four of the primers,
namely OPG2, OPG3, OPG9 and OPG14, produced polymorphic bands. Thus results
showed that the accessions 308-B and 423-B were differentiated from the other accessions
by primer OPG3 while 308-B was differentiated from 423-B and the rest by primer OPG14.
Accessions 451-C and 428-D were differentiated from the other six accessions by primer
OPG2. The primer OPG8 differentiated accession 428-D from 451-C and the rest. It was
clearly shown that only accessions 309-B and 448-D were similar and confirmed as
duplicates (Fig. 3).
14 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
3
0
8
B
D
i
s
t
a
n
c
e
1.6 +
|
|
1.4 +
|
|
1.2 +
|
|
1 +
|
|
0.8 +
|
|
0.6 +
|
|
0.4 +
|
|
0.2 +
|
|
0 +
3
0
9
B
4
4
8
D
4
5
1
C
4
2
8
D
4
2
3
B
_______________________________
.
_________________________
.
_________________________
.
_________________________
.
_________________________
.
_________________________
.
_________________________
.
_________________________
.
_________________________
.
_________________________
.
___________________
.
.
___________________
.
.
___________________
.
.
___________________
.
.
___________________
.
.
___________________
.
.
_____________
.
.
.
_____________
.
.
.
_____________
.
.
.
_____________
.
.
.
_______
.
.
.
.
_______
.
.
.
.
_______
.
.
.
.
_______
.
.
.
Fig. 3 Dendogram from cluster analysis on six sweetpotato duplicates based on RAPD banding
pattern using 9 primers
15
References
MOA. 2000. Keluasan Tanaman Pelbagai (Area of Miscellaneous Crops). Kementerian
Pertanian Malaysia, Kuala Lumpur, Malaysia.
Saad, M.S. 1995. Planting sweetpotato germplasm in culverts. SAPPRAD Newsletter
9 (1):14.
Saad, M.S. 1996. Genetics and variabilities of starch, protein, fibre and ash in
sweetpotatoes from Malaysia. Selected Research Papers 94/95 (Vol. 2 –
Sweetpotato):203-210.
Saad, M.S., M.S. Ramisah, A.G. Yunus, E. Nissila and M.S. Nordin. 1999a. Application
of RAPD markers in duplicate detection in sweetpotato germplasm. Presented at
a Symposium on Genetic Resources of Borneo, Kota Kinabalu, Sabah, Malaysia,
26–28 October 1999.
Saad, M.S., T.C. Yap, A.G. Yunus, M.A. Kadir and M.S. Nordin. 1999b. Genetic diversity
within and between locally adapted sweetpotato germplasm from different subregions of Sarawak and Sabah, Malaysia. Presented at a Symposium on Genetic
Resources of Borneo, Kota Kinabalu, Sabah, Malaysia, 26–28 October 1999.
Saad, M.S. and A.G. Yunus. 1996. The determination of starch in sweetpotato roots using
near infrared (NIRS) reflectance spectroscopy. Presented at the 1st Asian Sweetpotato
and Potato Research and Development Meeting, Malang, Indonesia, August 27–
30, 1996.
16 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
In Vitro Conservation of Sweetpotato Germplasm
Guo Xiaoding1, Zhou Ming-De2 and Wang Yi3
1 Xuzhou Sweetpotato Research Centre, Xuzhou, Jiangsu Province 221121, China;
2 Eastern Asia Office, International Plant Genetic Resources Institute, Beijing 100081;
3 Liaison Office in Beijing, International Potato Centre, Beijing 100081, China
Introduction
Sweetpotato is a vegetatively propagated crop with high yield and nutritional value.
Sweetpotato is highly efficient in converting light energy into organic matter. Generally,
the roots are used, but the leaves are also edible and widely consumed in New Guinea
and East and Southern Africa. As new uses of sweetpotato are continuously being
developed, as medicine, as a source of natural pigments, etc., it is obviously very
important to carry out research on its germplasm. Hence there is the increased focus
on collecting and conservation of sweetpotato germplasm.
Evaluation of conservation system of sweetpotato germplasm
Sweetpotato is propagated by using roots, shoot tops and stem segments. In the
temperate region, the principal reproductive organ is the root, which contains a high
percentage of water, approximately 65–85%. Because of their bulkiness, sweetpotato
storage roots are difficult to store and transport. Owing to its hexaploid nature and
hybrid origin, sweetpotato offspring segregates, and the unique genetic constitution
of the parents is lost in the progeny. The plant is an out-breeder and homozygous loci
are therefore rare. Sweetpotato genotypes fall into different cross sterility groups. Crosses
between genotypes of a given group result in no or very low fruit and seed set.
Clonal sweetpotato germplasm is currently conserved in field and in vitro genebanks
so as to make it available for exchange, evaluation and use in the long term.
Field genebank: In the temperate region sweetpotato is regarded as an annual crop because
of the seasonally determined cycle of bedding (for the production of propagules),
transplanting, harvesting and storage. However, in the tropics sweetpotato is regarded as
a perennial. In this case, the germplasm is continuously replanted for several years. Thus
a field genebank can be sustained in one site for a long term. Field maintenance offers several
advantages over in vitro conservation such as ease of operation, and no need for specialized
staff, costly equipment and sophisticated techniques. Field maintenance allows the agronomic
evaluation of germplasm for use in breeding and varietal improvement (Huang and Chen
1991). But this system has the following drawbacks as compared with in vitro maintenance:
1) Extensive land is needed (a problem in China and other densely populated countries).
For example, in Xuzhou, China, 12 plants are maintained per accession. They occupy
a plot of 2.55x2.25 m. Thus, 1000 accessions require approximately 0.6 ha;
2) Labour costs. Field maintenance involves bedding, transplanting, harvesting and
storing, which must be repeated every year;
3) Disease build-up especially of virus, and subsequent decline of plant vigour,
frequently resulting in loss of the materials;
4) Poor ecological adaptation of certain accessions to the maintenance site often results
in loss of material due to drought, water logging (rotting) or inappropriate storage
conditions. Poor adaptation to edaphic or climatic conditions may also lead to plants
not forming storage roots;
5) Theft of genetic material;
17
6) Bulkiness of propagating material for transport;
7) Quarantine restrictions of field-grown sweetpotato, especially for the international
movement of germplasm.
In vitro genebank: There are three methods for conserving sweetpotato germplasm
through in vitro maintenance: 1) as test tube plantlets, which is the most common form;
2) as artificial seed, developed in recent years; and 3) cryopreservation for long term
storage. All these methods precede by tissue culture. In the following, we will analyze
and compare these methods.
Unlike field maintenance, in vitro conservation can be carried out without
consideration of climatic and edaphic factors, resulting in a high propagation coefficient.
Under the sterile conditions of in vitro culture, the plantlets can be maintained free
from diseases, viruses and pests. Owing to labour and space saving, more germplasm
can be conserved. Tissue culture also allows the conservation of special material, such
as outbreeding offspring and the plants produced by somatic hybridization (Xia and
Zhu 1987), or materials bearing resistant genes but not producing storage root. In vitro
materials occupy less volume and are more convenient for transportation than field
grown propagules. There is less restriction in quarantine when the materials are
exchanged internationally (Engelmann 1991).
However, in vitro maintenance has disadvantages. In vitro plantlets cannot be
characterized and evaluated like field-grown plants. Tissue culture requires electrical
energy for the refrigeration of culture rooms and the operation of critical equipment.
This is not only expensive but also makes in vitro culture vulnerable to power cuts,
which can be common in developing countries. Requirements of hygiene in tissue culture
are very strict; otherwise contamination by microbes will lead to loss of the materials.
Moreover, tissue-cultured material is prone to the occurrence of somatic variation, which
remains hidden, whereas most asexual variants can be eliminated in field-grown material
where they manifest themselves as changes in colour or shape (Engelmann 1991). In
developing countries, the prices of some consumables, such as electric power, chemical
reagents, etc., are relatively high, so the cost of in vitro conservation is more expensive
than that in field genebank.
Cryopreservation of plant germplasm has been explored in recent years for its
potential for long-term conservation. Some success in cryopreservation of potato and
cassava has been achieved. Thus, short- to middle- and long-term in vitro conservation
complement each other to make a combination of conservation and application of
sweetpotato germplasm (Fig. 1). In Fig. 1, base collection is conserved under long-term
conditions, which, without considering application, emphasizes on gaining the highest
safety factor in order to avoid loss of the materials, while active collection is used for
germplasm evaluation and distribution, and gives more attention to application.
Botanical seeds: In the first ANSWER meeting held in 1996, the possibility of conserving
germplasm by applying botanical seeds was discussed. Sweetpotato has orthodox
botanical seed, meaning they withstand desiccation and can be stored at low
temperatures (refrigerated or frozen) for decades without significant loss of
germinability. As an outbreeder and owing to its hexaploid and heterozygous nature,
sweetpotato seed progenies release much variation and thus cannot be maintained true
to type. Therefore, storage of seeds is not used for sweetpotato germplasm conservation
in China (Guo et al. 1996). However, if the conservation of genes as opposed to the
maintenance of genotypes is considered in the future, the botanical seeds spontaneously
produced or obtained through artificial hybridization could be a suitable method for
long-term conservation.
18 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
In vitro genebank
Active Collection
Slow growth conservation
Base Collection
Shoot tip cryogenic storage
Artificial seeds plantlets
Micropropagation
International germplasm exchange
National Programme
Germplasm Conservation Center
Fig. 1 In vitro conservation, exchange and utilization of sweetpotato germplasm
Methods of in vitro conservation
Test-tube plantlets: By combining suitable physical and chemical factors slow growth
or minimal growth can be induced during tissue culture in order to facilitate extension
of length of conservation. These factors are described as follows:
1) Temperature of culture room. The most suitable temperature for sweetpotato tissue
culture is 26–28°C. At 18–20°C, its growth is retarded. Jarret and Florkowski (1991)
reported that when culture temperature was reduced from 21.1 to 15.6°C, growth
of the in vitro plantlets was reduced to 50%. Temperature reduction is the usual
method to slow down plantlet growth thus extending the time between regenerations
(Xin 1985; Lin and Li 1989; Huang and Chen 1991; Bertrand-Desbrunais et al. 1992;
Van den Houwe et al. 1995; Angel et al. 1996).
2) Illumination. Normally test-tube plantlets are grown under 14–16 hr photoperiod
conditions with light intensity of 3000–4000 lx. When the photoperiod is reduced
to 8–10 hr and light intensity to 1000 lx (Xia and Zhu 1987; Xin 1987; Song et al.
1991), rate of photosynthesis is reduced and growth will be retarded. Jarret (1991)
observed that, when the photoperiod was reduced from 16 to 4 hr, the plantlets
could grow normally even though they showed some chlorosis. To date there is
no report concerning the influence of light quality on storage of sweetpotato testtube plantlets.
3) Atmosphere. Reducing pressure of oxygen partially slows down the metabolism of
cells and favours plantlets storage (Xia et al. 1989), but it needs more complex facility
and equipment, thus it is not practical.
19
Experiments have also shown that it is also possible to inhibit the growth of test-tube
plantlets with addition of special chemicals to the conservation medium:
1) Phytohormone: Higher concentrations of ABA (abscissic acid) and KT (kinetin) can inhibit
the growth of tube-cultured plant. For example, 1–10 mg/l ABA can completely inhibit
the growth of the axillary bud, but when the plant hormone is removed from the growth
medium the plant begins to grow normally (Xin 1987; Xin 1989a; Jarret and Florkowski
1991). The survival ratio of the tissue-cultured sweetpotato after one-year conservation
reaches 71.3%, if 10 mg/l KT is added to the MS culture medium (Xin 1989a; 1989b). Beyond
a certain concentration of ABA, however, the survival ratio declines (Lin and Li 1989).
2) Growth inhibitor: If used at proper concentrations, the inhibitor can retard the
growth of the tube-cultured plants, as shown in potato and taro (Lin and Li 1989;
Song et al. 1991). Glyphosate (1 mg/l), CCC (cycocel, 100–500 mg/l) (Xin 1989a),
methyl succinic acid (50–70 mg/l) (Zhou 1987) and paclobutrazol (PP333, 3–5 mg/
l) (unpublished data) served to inhibit the growth of tube-cultured sweetpotato.
Some other known inhibitors are B9 (dimethyamuno succinamic acid, 10–30 mg/
l) (Zhou 1987) and MH (maleic hydrazide, 10 mg/l) (Xia and Zhu 1987).
3) Hyperosmolar material: Addition of some hyperosmolar material such as sucrose,
mannitol and sorbitol, etc., can lower the rate of water and nutrient absorption by the
plantlets from the medium resulting in retarded growth of the culture. Among these
materials, mannitol is widely used in the germplasm conservation using tissue culture
methods (Huang and Chen 1991; Song et al. 1991). The appropriate mannitol concentration
in sweetpotato is 1–1.5% (Xin 1989a; Jarret 1991;) and plants will be injured at higher
concentration (Huang and Chen 1991). Other experiments demonstrate that a high pH
value accompanies the mannitol after autoclave sterilization (Liang 1987).
4) Carbon resource: The decrease of the sucrose concentration in the culture medium
from 30 to 15–20 g/l can induce slow growth (Jarret 1991). Both higher and lower
sucrose concentrations can weaken the tissue culture growth, resulting in retarded
biomass accumulation (Lo and Liao 1993). Sucrose acts as the carbon resource and
balances osmotic pressure. Different carbon resources have different effects. For
example, if 3% glucose replaces sucrose, the culture shows weak growth. If lactose,
maltose, mannose, galactose or arabinose is used as the carbon source, the culture
will fail to grow after some time (Lo and Liao 1993).
Artificial seed: The recently developed technique of artificial seed was intended for
agricultural production purpose. Tang et al. (1994) demonstrated the utility of axillary bud
as artificial seed of sweetpotato. Nowadays, artificial seed is considered as a method of
germplasm conservation (Guo et al. 1997). The production of artificial seed involves the
following steps: stem segments with axillary buds (about 3 mm long) of plantlets in vitro
are encapsulated by 4–5% sodium alginate in MS culture medium, packing the resulting
beads in petri dish or test tube for storage. The artificial seed can be transplanted from
tissue culture onto horticultural substrates thus ensuring good genetic stability.
Using artificial seed has the following advantages:
1) Saving space for conservation. A petri dish or a test tube can contain 50 pieces of
artificial seed and thus replace 15 conventional culture tubes that are usually
necessary for one accession.
2) Extending the intervals between reculturing. After transplanting onto the culture
medium, the artificial seed germinate in approximately a month; when kept in a
storage room (18–20°C) the germination can be retarded for about two months.
3) Artificial seed show stronger regeneration ability. They can continue to grow in
the culture medium into young plants, or they can directly be grown on horticultural
substrate. When planted in sand, in vermiculite and in perlite, artificial seed
germinated normally (unpublished data).
20 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Cryopreservation
The advantages of cryopreservation include minimum space requirements for germplasm
storage, no need for reculturing and low incidence of somaclonal variation. This method
makes conservation of genetic resources very simple and thus can promote better
conservation efforts. Conserving apical tips of potato and cassava by cryopreservation yielded
promising results. The differences in viability of material conserved in liquid nitrogen for
between 3 months and 4 years are not significant (Bajaj 1985). Cryopreservation was also
employed for sweetpotato to assess the viability of the material from shoot tip and
embryogenic tissue (Towill and Jarret 1992; Blakesley et al. 1997). Although the
cryoconservation of embryogenic tissue presents fewer problems than dealing with shoot
tip, the genetic stability shown by shoot tip is better than by the former. Towill and Jarret
(1992) reported the first successful case of conserving the sweetpotato shoot tips from plantlets
in vitro in liquid nitrogen through vitrification. The highest viability of the cryopreserved
shoot tips from two sweetpotato clones was 83%. Vitrification presents no technical problems,
since no programmed cooling machine is needed. The components of vitrification solution
were 30% glycerol+15% ethanediol+15% dimethyl sulfoxide (DMSO). After storage in liquid
nitrogen, part of the shoot tips treated by vitrified solution produced plantlets in the recovery
medium (Towill and Jarret 1992). Further research is needed to make cryopreservation a
routine method for the long-term conservation of sweetpotato genetic resources.
The genetic stability of in vitro conservation
Genetic stability evaluation of the material conserved in vitro: There should not be
differences in phenotype between the materials maintained in the field and the ones
regenerated from in vitro conservation. So it is very important to do morphological
characterization. Based on the investigation, some biochemical analysis should be
employed to detect if variation has occurred in in vitro material, as evidenced by changes
in its soluble protein or isoenzyme patterns (Dodds 1988). DNA-based techniques such
as RAPDs, developed in recent years, have improved the detectability of genetic changes
at the molecular level.
Age limit of conservation: According to our research (unpublished), after 8–10 years
conservation of sweetpotato plantlets in vitro in a medium containing 1% mannitol,
no genetic changes occurred judging from isoenzyme and RAPD patterns. However,
it is not sure whether the genetic changes occurring are directly related to the length
of time they are conserved. There also seemed to be differences in rates of genetic change
among different genotypes conserved in vitro which need to be studied. It is suggested
that in vitro conservation and field maintenance should be undertaken in a
complementary mode, which will guarantee the safety of the conserved germplasm.
Research has shown that the ratio of genetic variation of somatic tissue from a vegetatively
propagated crop conserved in vitro is relatively high. In the presence of external stimuli,
the variation tends to appear more frequently. Chromosomal variation can also be induced
by tissue culture (Shang 1984). Table 1 shows that high concentration of chemicals in culture
medium can induce variation (Xin 1989b). Morphological changes induced by mannitol
are reversed under field conditions, but they are not with media containing growth inhibitors
like KT and CCC (Wang et al. 1989). Using DNA probes to evaluate genetic stability of potato
plants after in vitro maintenance showed that there were no RFLP alterations in cryopreserved
plants, but there were alterations in plants regenerated from slow-growth media (using
mannitol) (Harding 1991). Using DNA markers it has been shown that plantlets produced
through shoot tip or meristem culture are more genetically stable than those produced
through a method that has a callus phase in it, as somatic variation is less in the former
(Muller et al. 1990; Potter 1991).
21
Table 1. The effects of three chemicals and their concentrations on the growth and stem colour
of in vitro plants of sweetpotato variety Yiwohong (Xin 1989b)
Treatment
Concentration (mg l 1)
Yield per plant (g)
Stem colour
Kinetin
5
420
purple
10
450
green
Mannitol
15000
410
purple
30000
100
green
ABA
0.5
230
purple
1.0
175
purple
10.0
75
green
CK
0
389
purple
Conclusion
Currently, in vitro conservation of sweetpotato germplasm takes the form of
micropropagated plantlets in test tubes from shoot tips. The system of artificial seed
should be improved to provide an alternative to conventional tissue culture.
Cryopreservation of sweetpotato can be achieved through encapsulation and
dehydration, which will avoid the variation caused by injury through vitrification
solution. Sweetpotato tissue culture protocols can also be improved by adding mannitol
and reducing sucrose or glucose in slow growth conserving medium, by the use of nodal
segment for propagation, conserving the material under conditions of 18–20°C, 8–10 hr
photoperiod, 1000–2000 lx luminous intensity. The genetic stability should be evaluated
by a combination of morphological characterization and molecular assessment.
References
Angel, F., V.E. Barney, J. Tohme and W.M. Roca. 1996. Stability of cassava plant at the
DNA level after retrieval from 10 years of in vitro storage. Euphytica 90:307-313.
Bajaj, Y.P.S. 1985, Cryopreservation of germplasm of potato (Solanum tuberosum L.) and
cassava (Manihot esculenta Crantz): viability of excised meristems cryopreserved
up to four years. Indian Journal of Experimental Biology 23:285-287.
Bertrand-Desbrunais, A., M. Noirot and A. Charrier. 1992. Slow growth in in vitro
conservation of coffee (Coffea spp.). 2. Influences of reduced concentrations of sucrose
and low temperature. Plant Cell, Tissue and Organ Culture 31:105-111.
Blakesley, D., T. Percival, M.H. Bhatti and G.G. Henshaw. 1997. A simplified protocol
for cryopreservation of embryogenic tissue of sweetpotato (Ipomoea batatas [L.] Lam.)
utilizing sucrose preculture only. Cryo-Letters 18:77-80.
Dodds, J.H. 1988, Review of in vitro propagation and maintenance of sweetpotato
germplasm. Pp. 185–192 in Exploration, Maintenance and Utilization of Sweetpotato
Genetic Resources. CIP, Peru.
Engelmann, F. 1991. In vitro conservation of tropical plant germplasm – a review.
Euphytica 57: 227-243.
Guo, X.D., D.F. Ma, H.M. Li and J. Tang.1997. Sweetpotato breeding and artificial seeds
conservation in China. Pp. 119–130 in Proceedings of MAFF-PRCRTC International
Workshop (L. Rolinada and Talatala-Sanico, eds.). MAFF, Tsukuba.
Guo, X.D., B.F. Song and M.D. Zhou. 1996. Status of sweetpotato germplasm research
in China. Pp. 70–76 in Proceedings of the Workshop on the Formation of A Network
for the Conservation of Sweetpotato Biodiversity in Asia (V. Ramanatha Rao, ed.).
IBPGR, Singapore.
Harding, K. 1991. Molecular stability of the ribosomal RNA genes in Solanum tuberosum
plants recovered from slow growth and cryopreservation. Euphytica 55:141-146.
Huang, J.H. and Sh.R. Chen. 1991. In vitro storage of ginger germplasm. Journal of
Southwest Agricultural University 13(3):310-312 (in Chinese with English summary).
22 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Jarret, R.L. 1991. Chemical and environmental growth regulation of sweetpotato (Ipomoea
batatas [ L.] Lam.) in vitro. Plant Cell, Tissue and Organ Culture 25:153-159.
Jarret, R.L. and W.J. Florkowski. 1991. Abscisic acid-induced growth inhibition of
sweetpotato (Ipomoea batatas L.) in vitro. Plant Cell, Tissue and Organ Culture 24:1318.
Liang, H.M. 1987. Points for attention of using mannitol as osmotic addition in plant
tissue culture. External Crop Tissue Culture 21:123-124 (in Chinese).
Lin, Ch.Ch. and Q.W. Li. 1989. Elimination of potato viruses and preservation of the
potato germplasm by the method of tissue culture. Journal of Potato 3(2):73-78 (in
Chinese with English summary).
Lo, S.F. and C.H. Liao. 1993. Studies on the in vitro maintenance techniques of
sweetpotato (Ipomoea batatas L.) I. Influence of carbon sources. Journal of Agricultural
Research, China 42(1):30-36 (in Chinese with English summary).
Muller, E., P.T.H. Brown, S. Hartke and H. Loez. 1990. DNA variation in tissue-derived
rice plants. Theoretical and Applied Genetics 80:673-679.
Potter, R. 1991. An assessment of genetic stability of potato in vitro by molecular and
phenotypic analysis. Plant Science 76:239-248.
Shang, X. M. 1984. The chromosome variation in plant tissue culture. Journal of
Cytobiology 6(1):5-12 (in Chinese).
Song, M., X.J. Wang and Sh.R. Chen. 1991. In vitro preservation and propagation of
taro. Journal of Southwest Agricultural University 13(4):409-412 (in Chinese with
English summary).
Tang, Sh.H., M. Sun, K.P. Li and Q.T. Zhang. 1994. Studies on artificial seed of Ipomoea
batatas L. Lam. Acta Agronomica Sinica 20(6):746-750 (in Chinese with English
summary).
Towill, L. E. and R.L. Jarret. 1992. Cryopreservation of sweetpotato (Ipomoea batatas [L.]
Lam.) shoot tips by vitrification. Plant Cell Reports 11:175-178.
Van den Houwe, I., K.D. Smet, H.T. Momtcel and R. Swennen. 1995. Variability in storage
potential of banana shoot cultures under medium term storage conditions. Plant
Cell, Tissue and Organ Culture 42:269-274.
Wang, Y.H., J. Tang, X.D. Guo and J.Y. Wu. 1989. Preliminary study on genetic stability
of sweetpotato (Ipomoea batatas L.) maintained in vitro. Pp. 204-209 in A Treatise
on Storage of Crop Germplasm Resources (Y. Sh. Ma, ed.) (in Chinese with English
summary).
Xia, X.Zh. and F.M. Zhu. 1987. Studies on storage medium for tube seedling of potato.
Acta Agriculturae Boreali-Sinica 12(1):37-42 (in Chinese with English summary).
Xin, Sh.Y. 1985. Preservation of sweetpotato germplasm by tissue culture. Crop Genetic
Resources 3:24-26 (in Chinese).
Xin, Sh.Y. 1987. Studies on meristem culture and in vitro preservation of sweetpotato.
Crop Genetic Resources 4:34-36 (in Chinese).
Xin, Sh.Y. 1989a. Technology and condition for germplasm for germplasm preservation
of sweetpotato (Ipomoea batatas Lam.). Pp. 2–9 in A Treatise on Storage of Crop
Germplasm Resources (Y. Sh. Ma, ed.) (in Chinese with English summary).
Xin, Sh.Y. 1989b. Effects of chemical on the preservation of sweetpotato germplasm.
Pp. 10–15 in A Treatise on Storage of Crop Germplasm Resources (Y. Sh. Ma, ed.)
(in Chinese with English summary).
Zhou, M.D. 1987. The effects of methyl succinic acid on growth and preservation of
plantlets of sweetpotato in vitro. Crop Genetic Resources 4:27-28 (in Chinese).
23
Fig. 1 The artificial seeds of 8 sweetpotato varieties were conserved at 18–
20°C for 4 months
Fig. 2 Harvest of sweetpotato germplasm in late October in Xuzhou sweetpotato
field genebank
24 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Fig. 3 Plant grown on perlite culture medium for 4 months grown from artificial
seeds of cultivar Xushu 18 conserved for 5 months
Fig. 4 Plantlets grown from artificial seeds of 4 sweetpotato cultivars after
inoculating on MS medium supplemented with 1% mannitol (130 days)
25
Present Status of Sweetpotato Germplasm Conservation in
Indonesia
M. Jusuf1, St.A.Rahayuningsih1 and Minantiyorini2
Institute for Legume and Tuber Crops, Malang, Indonesia;
2Research Institute for Food Crops Biotechnology, Bogor, Indonesia
1Research
Introduction
Indonesia, Papua New Guinea and the South Pacific islands are generally regarded
as the secondary centre of genetic diversity. In Indonesia, sweetpotato is cultivated in
various agroecological zones ranging from the humid tropics to subalpine regions over
3000 masl.
In general, most sweetpotato farmers in Indonesia still use hundreds of local cultivars
planted in different environments. Farmers have for a long time used these local cultivars
which are well adapted to different soil and climatic conditions. Naturally, local clones
have developed resistance to environmental stresses and major pests and diseases.
Therefore, they constitute very valuable genetic resources for the breeders.
The cultivars used by the farmers in Indonesia are different from one region to
another. In Java, the farmers grow one or two of the most popular cultivars in large
areas with, to a lesser extent, several additional but less popular ones. This practice
apparently may cause genetic erosion and endanger future breeding efforts (Manwan
and Dimyati 1989). In contrast, in Irian Jaya the farmers usually grow a large number
of cultivars in a particular field. However, they prefer early-maturing varieties, which
can lead to the loss of late-maturing cultivars. This is supported by recent findings
of late-maturing cultivars becoming rare (La Achmadi 1988).
So far, over 1155 accessions have been conserved at CRIFC (RILET and RIFCB).
Among these, 427 local cultivars of Irian Jaya were received from CIP-ESEAP, Bogor,
and are being conserved in these two institutes. Accessions conserved include released
varieties, elite breeding lines, local cultivars and introductions.
Up to now, sweetpotato germplasm is maintained in the field using stem cuttings
and sprouts for propagation and in tissue culture. Accessions maintained in the field
genebank are harvested 4–5 months after planting thus allowing two re-plantings per
year. About 200 accessions are conserved in in vitro culture and cryopreservation is
being studied.
Germplasm conservation and management
Current status of sweetpotato germplasm conservation
Sweetpotato germplasm conservation is a complex activity and includes both clonal
maintenance and seed conservation. Agencies involved in the germplasm conservation,
evaluation and utilization in Indonesia include the two research institutes under the
Central Research Institute for Food Crop (CRIFC), namely the Research Institute for
Legume and Tuber Crops (RILET) and the Research Institute for Food Crops
Biotechnology (RIFCB), Cendrawasih University in Irian Jaya as well as CIP-ESEAP
Regional Office in Bogor.
Considerable progress has already been made in terms of numbers of accessions
of sweetpotato genetic resources maintained at CRIFC. To date, over 1155 accessions
have been conserved at two research institutes: RIFCB in Bogor and RILET in Malang.
26 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Compared to 3 years ago (623 accessions), the number has increased considerably
because more accessions have been received from CIP-ESEAP, Bogor, especially Irian
Jaya collection and also exploration carried out by RIFCB and RILET. Accessions include
released varieties, elite breeding lines, local cultivars, and introductions (Table 1).
Table 1. Numbers of sweetpotato accessions conserved in Indonesia in 1996 and 1999
*Source: Jusuf et al. 1996.
1996*
1999
Sources of collection
Number Percentage (%)
Number Percentage (%)
1. Improved varieties
3
0.5
8
1
2. Native cultivars
501
80
916
79
3. Introductions
17
3
32
3
4. Breeding lines
102
16
199
17
Total
623
100
1155
100
Aside from CRIFC, CIP-ESEAP and Cendrawasih University (in Manokwari Irian Jaya)
also maintain sweetpotato collections, especially in situ collection of Irian Jaya
germplasm. To minimize duplication, national coordination is needed to enable
institutions and scientists involved in sweetpotato germplasm conservation to become
more efficient and effective in defining and accomplishing relevant and significant work.
From Table 1, it can be seen that that most of the collections come from native cultivars
with 916 accessions (79%) followed by elite breeding lines (199; 17%). Of the native
cultivars, about 426 accessions (47%) are Irian Jaya germplasm donated by CIP-ESEAP
region in 1998. All the information on Irian Jaya germplasm has been computerized
by CIP-ESEAP and a database is maintained in Bogor. In addition to Irian Jaya
germplasm, collection from Java contributes 253 accessions (28%) followed by
Nusatenggara (83; 9%) and Maluku (40; 4%) (Table 2). The following quality characters
have been determined for 101 accessions: fibre, sugar, starch, and total soluble solid
and water contents. The results of this analysis are given in Appendix 1.
Table 2. Numbers of native sweetpotato cultivars in Indonesia (by Island of origin) conserved
in the field
*Source: Jusuf et al. 1996.
Island of origin
1996
1999
Number Percentage (%)
Number Percentage (%)
1. Sumatera
241
48
56
6
2. Java
167
33
253
28
3. Bali
46
9
46
5
4. Nusa Tenggara
33
7
83
9
5. Kalimantan
0
0
5
1
6. Sulawesi
14
3
40
4
7. Maluku
0
0
7
1
8. Irian Jaya
0
0
426
47
Total
501
100
916
101
Field genebank conservation
At CRIFC, the field genebank is utilized for ex situ conservation (maintenance) while
Cendrawasih University and CIP-ESEAP practise both in situ and ex situ conservation
methods.
For a vegetatively propagated crop like sweetpotato, ex situ conservation strategy
in field genebank is by far the most practical way. These ex situ collections need to
be fully characterized, evaluated, and information documented in a form that can be
27
easily accessed nationally and internationally. RILET and RIFCB are the two research
institutes that maintain sweetpotato germplasm under field genebank conservation.
It is planted twice a year with cuttings obtained directly from the old field or from
sprouts derived from roots. Plot size for each accession is 1.0 m x 2.5 m with ten cuttings
per row. Sweetpotato conservation activities are very complex, tedious and require much
labour. Every year, all germplasm accessions are raised in a nursery to get planting
materials and a large field is utilized for producing the new roots of each accession.
It is re-established once a year with sprouts obtained directly from the regenerated row.
Complementary conservation technology
Due to maintenance problems of field genebanks, alternative conservation methods
are needed such as in vitro maintenance, on-farm conservation (in situ) or as botanical
seed conservation and cryopreservation.
In vitro conservation
Field genebanks are labour intensive and require much field space. To back up field
collections of important cultivars/accessions, in vitro maintenance is employed. This
is to safeguard important collections being lost due to biotic and abiotic stresses. An
in vitro genebank has, therefore, been initiated to eliminate some of these problems.
The genebank also acts as a duplicate collection of germplasm maintained in the field.
Maintenance in vitro has its advantages vis-à-vis field genebank, to avoid loss of
material due to natural calamities, as well as diseases. However, a major problem with
this is genetic instability, as variations can easily occur during the in vitro maintenance,
especially the somatic mutations as this is a clonal propagated crop. In vitro conservation
is generally more secure, less expensive and labour intensive than seed root storage.
It is also helps in exchanging healthy genetic resources as tissue cultured materials can
be made free of insects and diseases; thus in vitro conservation is an excellent technology.
However, in vitro material cannot be evaluated and characterized as is possible with
field-grown material. At this moment as many as 200 accessions are conserved in vitro
and they are subcultured once a year at RIFCB in Bogor.
In situ conservation
In situ conservation or on-farm conservation is now given emphasis because of the
recognition of farmers as the source and keepers of many landraces. Farmer managed
conservation would be complementary to an overall national crop germplasm
conservation effort (Prain and Piniero 1996). In situ conservation is very effective where
genetic diversity is high (Komaki 1998) such as in Irian Jaya and Nias Island in North
Sumatera (Jusuf et al. 1998). Therefore, this method seems to be adopted for
complementary conservation strategy, and CIP-ESEAP and Cendrawasih University are
maintaining Irian Jaya collection in in situ form in Irian Jaya.
Botanical seed conservation
At the last meeting of ANSWER, it was agreed that the sweetpotato collection could
be divided into three groups: 1. frequently used, 2. less frequently used, and 3. rarely
used. Group one consists of germplasm, which contains important traits and is frequently
used by sweetpotato workers. The group with less frequently used germplasm contains
interesting or potentially useful traits, which may become more important in the near
future. The group with rarely used germplasm includes diverse accessions with no
identifiable use at present or accessions similar to but not identical to accessions in
28 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
the first and second groups. It was felt that groups 1 and 2 could be conserved in the
field and/or in vitro genebank while group 3 could be conserved as seeds (Rao and
Schmiediche 1996). Botanical seed conservation can be complementary to clonal
germplasm conservation. Botanical seed storage effectively conserves genes contained
in original accessions rather than specific genotypes or specific gene combinations (Rao
and Schmiediche 1996). It is an inexpensive conservation method, but valuable traits
become apparent only after several years during evaluation of seed progenies (Komaki
1998).
Botanical seeds of sweetpotato have never been used as a storage material in
Indonesia. Although botanical seeds are easy to maintain and keep for the long term,
they have so far been used only in breeding programmes. At this moment 20 671 seeds
from 15 female parents are available (Appendix 2). These seeds come from polycross
nursery and open pollination.
Cryopreservation
Cryopreservation of cells and tissues is being examined as a promising approach. The
principle behind cryopreservation is to bring the cells into a non-dividing state by
subjecting the cultures to ultra-low temperature in liquid nitrogen (–196°C) in the
presence of cryo-protectants (Komaki et al. 1998; Yoshinaga 1998).
Cryoconservation appears to be the most secure method to conserve material for
a very long period, but it is also the most expensive one. If somatic embryo or
embryogenic callus is chosen for cryopreservation, then this method faces the problem
of somaclonal variation that may occur during the process of tissue culture (Yoshinaga
1998). At this moment research is undertaken at RIFCB (Research Institute for Food
Crop Biotechnology) to develop a protocol for cryopreservation of sweetpotato.
Problems with sweetpotato germplasm conservation: field genebank problems
Since sweetpotato is a vegetatively propagated crop, the major method of its conservation
has been to maintain field collections – a costly exercise in time, labour and space, unlike
sexually propagated crops that can be conserved as seed. As far as conservation of
sweetpotato germplasm in field genebank is concerned, the following problems are
encountered:
1. High cost maintenance of large collection
2. Risk of loss due to environment stresses
3. Germplasm materials are not fully characterized; thus duplicates continue to be
maintained
4. Lack of financial support
5. Mix-up of identification labels.
Experience shows that several collections maintained in field genebanks were lost/
missing due to drought, water logging and infestation of pests, including animals. In
order to solve these recurring problems, it is suggested to conduct a study on the
minimum number of accessions that needs to be maintained actively. This size should
be representative of the total genetic variability. Collection should be backed-up with
in vitro and botanical seed maintenance.
Documentation problems
RILET, RIFCB, CIP-ESEAP and Cendrawasih University have computerized all the
information on Indonesia sweetpotato germplasm. RILET and RIFCB maintain the
central database and share information on sweetpotato genetic resources, but sometimes
the institutions do not use common descriptors for characterization and management.
29
Other problems include: lack of expert staff to do characterization and documentation;
some characters are strongly influenced by environments; some accessions do not
produce roots, so that the root characters cannot be determined.
Exchange of germplasm problems
If germplasm is moved in the form of storage roots so are the diseases and insects present
on them. In vitro culture allows the elimination of bacterial, fungal and mycoplasma
infection. Within Indonesia, agencies working on sweetpotato freely exchange
sweetpotato germplasm materials. With agencies outside the country, Indonesia has
to abide by the agreement of the Asian Network for Sweetpotato Genetic Resources
(ANSWER) composed of 11 member countries, namely Indonesia, Malaysia, the
Philippines, Thailand, Vietnam, Sri Lanka, Japan, India, China, South Korea and Papua
New Guinea. It was agreed that each member country could exchange genetic materials
in reciprocal manner with due recognition of the material received.
References
Jusuf, M., St. A. Rahayuningsih, Minantyorini, and I.G. Mok. 1998. Sweetpotato breeding
and genetic conservation in Indonesia. Pp. 49–62 in Sweetpotato Genetic Resources
Conservation and Use in Asia (R.L. Tatala-Sanico, ed.). Proceedings of MAFFPRCETC International Workshop. Tsukuba, Japan.
Jusuf, M., Y. Widodo, St.A. Rahayuningsih and Suyamto. 1996. Sweetpotato genetic
resources in Indonesia. Status and future outlook. Pp. 41–45 in Proceedings of the
Workshop on the Formation of a Network for the Conservation of Sweetpotato
Biodiversity in Asia. CIP, Bogor, Indonesia, 30 April–5 May 1996 (V. Ramanatha
Rao, ed.). IPGRI-APO, Serdang, Malaysia.
Komaki, K. 1998. Sweetpotato breeding and genetic resources conservation in Japan.
Pp. 77–98 in Sweetpotato Genetic Resources Conservation and Use in Asia (R.L.
Tatala-Sanico, ed.). Proceedings of MAFF-PRCETC International Workshop.
La Achmadi, 1988. Sweetpotato cultivar and cultivation system in Baliem valley,
Jayawijaya Indonesia. Pp.103–142 in Proceedings of the Seminar on Rootcrops in
Irian Jaya. July 27–29, 1988. Manokwari, Irian Jaya.
Manwan, I. and Dimyati. 1989. Sweetpotato production, utilization and research in
Indonesia. Pp. 43–51 in Improvement of Sweetpotato (Ipomoea batatas) in Asia (CIP,
ed.). Report of the Workshop on Sweetpotato Improvement in Asia, ICAR,
Trivendrum, India. Oct. 24–28, 1988.
Prain, G. and M. Piniero. 1996. Communities as curators of plant genetic resources.
The case of rootcrop conservation in Southern Philippines, IDRC-UPWARD Funded
Project.
Ramanatha Rao, V. and P. Schmiediche. 1996. Conceptual basis for proposed approach
to conserve sweetpotato biodiversity. Pp. 8–15 in Proceedings of the Workshop on
the Formation of a Network for the Conservation of Sweetpotato Biodiversity in
Asia. CIP, Bogor, Indonesia, 30 April–5 May 1996 (V. Ramanatha Rao, ed.). IPGRIAPO, Serdang, Malaysia.
Yoshinaga, M. 1998. Cryopreservation of sweetpotato in Japan. Pp. 147–152 in
Sweetpotato Genetic Resources Conservation and Use in Asia (R.L. Tatala-Sanico,
ed.). MAFF/PRCRTC, Philippines.
30 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Appendix 1. Nutritional qualities of 101 germplasm accessions at
RILET, 1995
No.
Acc number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
MLG 12340
MLG 12501
MLG 12502
MLG 12503
MLG 12504
MLG 12505
MLG 12506
MLG 12507
MLG 12508
MLG 12509
MLG 12510
MLG 12511
MLG 12512
MLG 12513
MLG 2515
MLG 12516
MLG 12517
MLG 12518
MLG 12519
MLG 12521
MLG 12522
MLG 12523
MLG 12524
MLG 12525
MLG 12526
MLG 12527
MLG 12528
MLG 12529
MLG 12530
MLG 12531
MLG 12532
MLG 12533
MLG 12534
MLG 12535
MLG 12536
MLG 12537
MLG 12538
MLG 12539
MLG 12540
MLG 12541
MLG 12544
MLG 12545
MLG 12546
MLG 12547
MLG 12548
MLG 12549
MLG 12550
MLG 12551
MLG 12553
MLG 12554
Water
content
(% DB)
70.8
69.7
69.9
70.9
69.7
71.5
70.4
74.1
–
72.7
74.8
82.5
66.8
69.4
–
–
68.3
66.9
67.2
76.4
66.8
70.9
69.8
80.5
66.3
66.2
70.6
–
64.1
75.5
73.5
63.7
79.2
–
76.9
75.9
77.9
–
–
66.8
70.9
68.1
69.7
66.8
68.7
67.6
70.5
72.5
73.8
71.7
Fibre
content
(% DB)
–
3.6
3.9
3.8
3.7
3.2
3.5
–
4.5
–
5.1
5.0
2.4
2.9
2.9
3.8
2.8
2.7
2.9
4.1
3.0
3.4
–
5.0
3.0
3.4
3.4
3.0
2.8
4.0
3.4
3.6
4.0
4.6
4.0
4.0
–
3.5
3.3
–
–
3.7
3.6
3.5
3.5
3.4
2.9
3.2
–
2.9
Sugar
content
(% DB)
–
3.0
3.5
3.4
2.9
2.2
2.5
0.8
–
1.9
17.5
18.7
1.8
2.1
2.1
1.4
2.3
2.8
2.7
3.9
2.1
1.5
–
17.4
3.3
2.9
2.3
3.6
1.7
7.4
2.5
0.6
4.2
2.9
3.6
2.2
–
1.4
0.4
–
–
1.4
1.1
3.4
2.0
1.9
2.5
4.0
–
2.4
Starch
content
(% DB)
–
45.3
47.0
45.7
41.7
45.9
47.1
45.1
–
42.0
29.6
30.0
60.0
41.5
46.7
47.6
40.9
40.5
46.9
49.5
40.3
40.0
–
28.7
59.7
47.9
46.6
50.1
43.1
36.7
46.8
46.4
45.4
41.8
47.3
45.4
–
45.1
61.1
–
–
55.8
44.7
38.3
39.2
54.4
48.2
54.7
–
46.5
Total
soluble
solid (%)
8.4
9.0
8.2
8.0
8.5
6.7
6.8
7.6
–
7.2
7.7
7.4
8.8
7.4
–
–
8.0
8.8
8.5
6.7
8.5
8.3
8.2
7.6
10.4
9.2
8.9
7.3
9.9
6.4
7.4
8.0
8.0
7.4
8.1
8.2
–
–
–
8.5
7.5
8.8
8.7
9.2
7.2
7.7
8.8
8.4
7.4
8.8
31
No.
Acc number
51
MLG 12555
52
MLG 12556
53
MLG 12557
54
MLG 12558
55
MLG 12559
56
MLG 12560
57
MLG 12561
58
MLG 12562
59
MLG 12563
60
MLG 12564
61
MLG 12565
62
MLG 12566
63
MLG 12567
64
MLG 12568
65
MLG 12569
66
MLG 12570
67
MLG 12571
68
MLG 12572
69
MLG 12573
70
MLG 12574
71
MLG 12575
72
MLG 12576
73
MLG 12577
74
MLG 12578
75
MLG 12579
76
MLG 12580
77
MLG 12581
78
MLG 12582
79
MLG 12584
80
MLG 12585
81
MLG 12586
82
MLG 12587
83
MLG 12588
84
MLG 12589
85
MLG 12590
86
MLG 12591
87
MLG 12592
88
MLG 12593
89
MLG 12594
90
MLG 12595
91
MLG 12596
92
MLG 12598
93
MLG 12599
94
MLG 12600
95
MLG 12601
96
MLG 12602
97
MLG 12603
98
MLG 12619
99
MLG 12635
100
MLG 12699
101
MLG 12841
Note: ‘–’ data not available.
Water
content
(% DB)
72.8
67.8
60.4
70.2
72.9
–
74.1
72.3
70.4
72.8
71.3
73.1
73.7
74.2
73.9
67.7
73.8
73.7
69.2
70.9
71.3
72.6
73.2
70.1
79.2
63.6
78.1
77.1
73.3
71.3
71.8
–
69.3
71.1
77.9
69.4
72.6
71.3
73.0
72.1
74.4
74.4
72.4
77.9
68.2
–
78.7
62.2
78.9
69.8
–
Fibre
content
(% DB)
3.1
3.1
3.4
3.2
3.0
3.8
3.5
2.9
3.6
2.9
2.9
–
–
3.0
3.2
3.0
3.3
–
2.8
2.8
3.9
2.8
4.9
3.0
4.1
4.2
4.7
4.0
3.4
3.5
3.4
3.4
3.0
3.1
4.3
2.5
3.0
2.9
2.9
3.1
3.7
2.8
3.0
3.7
3.2
4.0
4.0
–
–
3.5
3.8
Sugar
content
(% DB)
5.3
1.7
5.8
3.1
3.5
1.0
5.4
3.2
4.2
0.6
3.2
–
–
3.2
3.0
1.9
3.1
–
2.0
1.3
6.0
1.3
1.8
2.0
3.1
3.4
2.3
2.5
1.6
1.9
4.2
3.9
3.4
2.7
9.2
1.0
1.7
1.1
1.7
1.8
2.8
3.9
3.9
3.8
1.9
1.9
2.1
–
–
2.9
1.8
Starch
content
(% DB)
45.6
47.4
48.3
52.2
55.2
47.8
45.9
50.2
46.6
46.4
58.3
–
–
45.0
47.1
47.4
44.9
–
55.0
48.2
46.4
49.0
40.8
51.1
37.3
39.7
43.6
40.7
52.8
53.9
55.2
46.8
59.6
53.7
33.8
56.4
56.6
56.5
60.7
51.1
59.7
59.6
48.3
55.6
57.9
42.6
39.1
–
–
47.8
62.5
Total
soluble
solid (%)
9.0
7.6
9.0
8.6
8.5
–
7.7
8.3
8.7
8.5
7.3
7.9
7.8
8.1
8.0
10.3
7.2
7.5
7.8
8.9
10.4
8.9
8.0
7.2
8.5
7.9
8.7
7.7
7.8
7.2
7.1
–
8.8
7.5
8.3
6.7
8.5
7.9
7.1
8.6
8.7
6.9
8.7
8.6
9.0
9.7
8.7
–
7.5
8.3
–
32 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Appendix 2. Number of botanical seeds from sweetpotato
germplasm collection at CRIFC, 1999
Name of cultivars
1. AB 94001-8
2. B 0053-9
3. Binoras Op 95-2
4. Cangkuang
5. Helalekeue baru
6. Helalekue
7. Hoboak
8. Inaswang Op 95-6
9. MIS 110-1
10. MLG 12588-1
11. Mikmak
12. Muara Takus
13. Musan
14. Siate
15. Wortel
Total
MLG #
CIP #
MLG 12830
MLG 12833
MLG 12831
MLG 12828
MLG 12950
MLG 12955
MLG 12962
MLG 12832
MLG 13274
MLG 12839
MLG 13066
MLG 12827
MLG 13083
MLG 13149
MLG 13241
–
–
–
–
W 0006
W 0220 B
W 0279
–
–
–
W 0121
–
W 0010
W 0319
W 0017
Number of
botanical seeds
20
978
2427
1675
375
480
444
2140
1729
5302
100
3783
330
513
375
20 671
34 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Conservation and Documentation of Sweetpotato Genetic
Resources in Irian Jaya
Ery Atmojo
The Root and Tuber Crops Research Centre, Cendrawasih University, Jl. Gunung Salju,
Manokwari, Irian Jaya, Indonesia
Introduction
In Irian Jaya, sweetpotato (Ipomoea batatas) plays an important role as the staple food.
In highland areas, sweetpotato is used as the main staple food, while in lowland areas
it is used mainly as a supplementary source of carbohydrate, or as a substitute for other
main staples like sago, taro or cassava, when the latter are not available. Besides, in
many parts of Irian Jaya, sweetpotato is also used as pig feed. In highland areas, the
importance of sweetpotato is indicated by the greatest dependence of people’s
subsistence on this crop (Schneider et al. 1993).
Although Central America is the place of origin, Irian Jaya is considered one of
the centres of diversity for sweetpotato. In this province, farmers usually grow a large
number of cultivars in any field (Jusuf et al. 1996). It is not known how many cultivars
exist in Irian Jaya, but Schneider et al. (1993) estimated that there are more than 1000
cultivars grown in the western part of the highland. As a comparison, there were 2775
accessions collected in Papua New Guinea (Guaf et al., 1996). Twenty percent of them
were identified as duplicates.
This paper will discuss briefly the recent progress on the conservation and the use
of sweetpotato in Irian Jaya, especially during the last three years.
Germplasm collection
During the last three years, there was only one collecting trip, conducted in early 1999
in Biak and Yapen islands in Northern Irian Jaya, which was conducted in collaboration
between the Rootcrops and Sago Research Centre (RSRC) of the Cenderawasih University
(Uncen), Manokwari, with the International Potato Centre (CIP) and Research Institute
for Legumes and Tuber Crops (RILET). Taro and other rootcrops were also collected.
A total of 55 sweetpotato accessions were collected from the lowland areas, 41 from
Biak, and 14 from Yapen. Passport data on all were also collected, but farmer (indigenous)
knowledge on the accession could not be collected. In two collection sites, sweetpotato
was found to be less important than taro.
Samples collected from Biak and Yapen have been accessed into a genebank in Prafi,
a transmigration area located 70 km from RSRC campus, or an hour by car, and have
been characterized using IBPGR (now IPGRI) descriptors. The new accessions raise the
total accession held by the RSRC up to 474 cultivars.
Field collections
The RSRC has its sweetpotato collection in two sites, one in Anggi (2100 m asl) and
the other in Prafi (100 m asl). At the present time, the Anggi site contains highland
accessions from around Wamena, which were collected in 1993. The Anggi site collections
are duplicates of collections maintained by CIP in Lembang, West Java. A total of 419
accessions were transferred from Lembang and planted in Anggi in February 1999, and
are in the process of being characterized. Prafi site contains lowland accessions from
Biak and Yapen. A total of 55 accessions were planted for the second planting season
35
in June 1999. Characterization for the first planting season has been made and
documented. About 15% were identified as duplicates and have not been eliminated.
In addition to 474 cultivars collected in Anggi site and Prafi site, around 100 cultivars
are maintained in Amban, at RSRC experimental station.
Conservation
Ex situ
The RSRC first collecting expedition was in late 1990 aimed at collecting sweetpotato,
taro and cassava. Exploration sites were Tigi, East Paniai, and Kamu subdistricts of
Paniai District. Besides, a number of accessions were also collected from Northern Biak
subdistrict, Biak-Numfor district. A total of 149 sweetpotato accessions were collected
in the expedition (Matanubun et al. 1991). The samples are maintained in Amban, at
RSRC experimental station. Another collecting expedition took place at Anggi in 1992
(Sawor et al. 1993). In addition, individual researchers have given a number of accessions
that they have collected in their own community service trips. In 1993, the size of the
collection had increased to 300 accessions from various parts of Irian Jaya.
Characterization of 300 accessions was carried out during November 1992 to March
1993 (Paiki 1993), and 204 accessions were characterized during August 1993 to January
1994 (Yaku et al. 1994).
Owing to the long dry season, presence of sweetpotato little leaf (SPLL) disease
(known as witches broom disease), and the lack of financial resources for the germplasm
maintenance, many accessions had died and the size of the collection had diminished
to around 100 accessions. To save the remaining sweetpotato cultivars from SPLL
infection, accessions obtained from highland areas were transferred to Anggi in 1994,
and recent accessions from Biak and Yapen were maintained in Prafi instead of Amban.
Anggi site is located 45 minutes by plane, south from Manokwari. Plane trips are
expensive and very infrequent and make it difficult to monitor Anggi site. It is difficult
to have someone to stay continuously to take care of the collection in Anggi due its
remote location.
In situ
The first in situ conservation site was established in central highland Wagawaga,
Jayawijaya, in 1994. The sweetpotato conservation garden is cultivated and managed
by the locals using farmers’ traditional practices. After a study of genetic diversity in
1995, a follow-up documentation of a total of 30 beds of sweetpotato was carried out
in 1998. The first study as well as the follow-up study counted 47 cultivars but only
27 cultivars were the same cultivars the farmers planted in 1994 and in 1998 (Prain
1999).
In early 1998, the conservation site was expanded. Wesaput, a village close to Wagawaga, and Kurima in the south of Wamena were chosen. In situ conservation study
in Wesaput involves a group of 24 women, and a group of 24 men. Documentation
of the women’s garden is in process, while it was reported that 33 cultivars out of 47
cultivars in the men’s garden have already been lost because of their characteristics
such as late maturity, low yield, etc. (Prain 1999). A total of 67 Irian Jaya cultivars,
together with 4 advanced clones were studied, and documentation is also in progress.
Because farmers were free to select cultivars they prefer and to eliminate cultivars
considered poor, genetic erosion seems to have taken place, and late maturity and low
yield cultivars could be lost.
36 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
In vitro
A study on in vitro conservation in RTSC was undertaken. A teaching staff of the Faculty
of Agriculture has conducted this study aimed at identifying a suitable medium for
in vitro growth of sweetpotato. Using fungicide and Bayclin (shirt whitening) for material
sterilization, and a combination of MS (Ubl) and coconut water as growth medium,
a suitable composition of medium has been identified. There are now 22 accessions
maintained in vitro. The research was financed by a grant from the Asian Development
Bank. Unavailability of fund has constrained the expansion of the research as well as
the expansion of sweetpotato in vitro conservation.
Utilization of sweetpotato genetic resources
Evaluation
Many studies to assess the agronomic performance of sweetpotato have been conducted
by a number of RTSC’s staff and a number of students of the Faculty of Agriculture
of Uncen in fulfilment of their undergraduate requirements. Unfortunately the researches
were not made in an integrated manner. As a result, there were little research results
that could be combined to make a recommendation on conservation or further use of
sweetpotato genetic resources. In addition, comparison of research results thus obtained
is also difficult. Similar was the case with other studies, such as response to a particular
pest or disease. The following are some conclusions of different studies, but these need
further confirmation.
Forty-eight cultivars have been evaluated for their agronomic performance. Prafi04 seems to produce a greater number of storage roots per plant, while seri and tiga
bulan seem to produce larger storage roots. Normally the experiments were conducted
in Amban and/or in Prafi.
Research on sweetpotato resistance to SPLL disease has revealed that 60 out of 220
cultivars studied were resistant to SPLL, while only 10 cultivars were highly susceptible.
A total of 50 cultivars have been tested for their tolerance to aluminium toxicity and
11 were found to be resistant, 9 not tolerant, and the remaining moderately tolerant.
Ten out of 20 cultivars evaluated for resistance to scab were found to be highly resistant,
and only 1 was highly susceptible. A total of 12 cultivars were involved in a number
of studies on sweetpotato resistance to Elsinoe batatas and 1 Irian Jaya cultivar (A-26)
showed a high level of infection, while 5 cultivars showed very low infection. Twentyfour cultivars were tested for resistance to Cylas formicarius and none was found to
be resistant to the pest, though 4 cultivars were moderately resistant to the pest.
Only 7 cultivars have been tested for their beta carotene concentration in the storage
root. Among them, Mouwebsi seemed to have the highest beta carotene content of around
5 mg/100 mg root flesh.
A study on scab intensity in Ransiki sub-district, and another study aimed at
detecting virus infection on sweetpotato are in progress.
Breeding
Efforts to breed improved sweetpotato has been limited so far. Research aimed at
determining the cross compatibility of 4 Irian Jaya cultivars revealed that cross
compatibility was higher when semuel was used as female and tinta as male. It was
also concluded that cultivar maria dan imobuna had the potential to be used as female,
while tinta as male. However, botanical seed is not available for any clonal accession
in the RSRC.
37
The RSRC has not produced breeding lines so far. However, there are several released
varieties held in Anggi and Amban sites, although the RSRC itself has not produced
any released variety. Many accessions collected from Wamena have been spread to
around the Anggi and Amban sites. Farmers around the two sites, and Uncen workers
have taken cuttings from germplasm to be cultivated in their gardens.
Documentation
Passport and characterization data of accessions in Prafi genebank have been stored
into a computer database. Similar data on accessions in Anggi site were also transferred
to RSRC from CIP. Characterization database obtained from CIP also contains images
of leaves and roots. A total of 1005 accessions have characterization data, and 527
accessions have passport data (at least the name of the district where the accessions
were collected). Other 174 accessions can only be identified as highland accessions,
and the remaining had no passport data. This is especially so with the accessions given
by individuals to the RSRC. Unfortunately, there are no accessions with farmer
(indigenous) knowledge documented.
Though there have been many studies related to sweetpotato conducted in the
Faculty of Agriculture of Uncen, results are dispersed in various units in the campus.
It is difficult to pool all the research results. Besides, uncoordinated research makes
it difficult to synthesize all the results. In turn, the researcher interested in studying
sweetpotato finds it difficult to get information needed to support his/her research.
Conclusion
Considering the various constraints, the following actions are suggested for
improvement of the status of Conservation and Documentation of Sweetpotato Genetic
Resources in Irian Jaya.
•
•
•
•
Contributions from individual researchers have indicated that there are still
sweetpotato growing areas unexplored. So it is suggested that further exploration
and collecting may be undertaken in such areas.
In order to improve documentation on sweetpotato genetic resources, a data
exchange system between various parties involved in the conservation of genetic
resources, especially between those who hold Irian Jaya accessions, must be set up.
In vitro conservation is a potential complementary method to field genebank. It needs
less space and labour. However, the cost of setting up this type of conservation would
be undoubtedly high. Besides, it needs educated and skilled staff to maintain the
collection. Support from other institutions to improve staff skills, and to raise fund
to set up and maintain accessions is needed.
In order to produce more productive and useful research, research policy must be
formulated by the RSRC.
References
Guaf, E., P.Van Wijmeersh and M. Otto. 1996. Conservation of sweetpotato germplasm in
Papua New Guinea. Pp. 35–40 in the Formation of a Network for the Conservation
of Sweetpotato Biodiversity in Asia, Proceedings of the Workshop (V. Ramanatha Rao,
ed.) Bogor, Indonesia. 1–5 February 1996. CIP and IPGRI. IPGRI-APO, Singapore.
Jusuf, M., Y.Widodo, St.A. Rahayuningsih and Suyamto. 1996. Sweetpotato genetic
resources in Indonesia. Status and future outlook. Pp 41–45 in Proceedings of the
Workshop on the Formation of a Network for the Conservation of Sweetpotato
Biodiversity in Asia. CIP, Bogor, Indonesia, 30 April–5 May 1996 (V. Ramanatha
Rao, ed.). CIP, Bogor and IPGRI. IPGRI-APO, Singaproe.
38 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Matanubun, H., F.A. Paiki and S. Taberima (eds.)1991. Eksplorasi I. Ubi-ubian di
Kabupaten Paniai dan Kabupaten Biak Numfor, Irian Jaya. Pusat Studi Ubi-ubian
Uncen. 51p.
Paiki, F.A. 1993. Laporan Penelitian Karakterisasi Morfologi Beberapa Kultivar Ubijalar
(Ipomoea batatas (L) Lam) Irian Jaya. Faperta Uncen. 42p.
Prain, G. 1999. The Maintenance and Utilization of Irian Jaya’s Sweetpotato Genetic
Resources, Progress Report, May 1997–April 1999. CIP, Bogor.
Sawor, T.P. Chadikun, et al. 1993, Interdisciplinary collection of Ipomea batatas L.
Germplasm and Associated Indigeneous Knowledge in Anggi, Irian Jaya, Indonesia.
Users’ Perspective with Agricultural Research and Development (UPWARD),
Universitas Anderawasih, International Potato Center (CIP)
Schneider, J., C. A. Widyastuti and M. Djazuli (eds.). 1993. Sweetpotato in the Baliem
Valley area, Irian Jaya, A report on collection on study of sweetpotato germplasm,
April–May 1993. CIP and RTCRC. 54 p.
Yaku, A., S. Taberima and N.L. Mawikere. 1994. Identifikasi Morfologi Beberapa Kultivar
Ubijalar Asal Dataran Tinggi Jayawijaya Irian Jaya. Faperta Uncen. 33p.
39
Sweetpotato Germplasm Conservation and Breeding in CIP-ESEAP
Tjintokohadi, N.L. Ningsih and Il Gin Mok
International Potato Centre (CIP), Regional Office for East, Southeast Asia and the Pacific
(ESEAP), Kebun Percobaan Muara, Jl. Raya Ciapus, Bogor 16610, Indonesia
Introduction
Conservation of genetic diversity within a crop species is the basis of all varietal
improvement. Therefore, collecting and conserving farmers’ varieties is an essential
activity before disseminating improved varieties. CIP-ESEAP has been working for
germplasm conservation since 1990. The activity includes collecting, maintenance, and
evaluation of germplasm.
Extensive evaluation focused on useful characteristics for crop improvement such
as resistance to scab, flowering and dry matter content. In practice, we grouped
accessions and combined with introduced seeds from various research institutes into
several subsets for seed production at polycross nurseries. The subsets included high
yield, high dry matter content, scab resistance, dark flesh colour, high pigmentation,
and earliness. Part of the seeds collected was used in breeding to develop good variety.
Distribution of advanced breeding clones as well as selected germplasm accessions
resulted in several new varieties. CIP-ESEAP produced more than 20 improved breeding
clones. These improved breeding clones have been distributed to many farmers,
institutes, NGO’s and private companies in Indonesia.
Collection
As the number of germplasm accessions has increased from collaborative efforts of CIP,
CRIFC, RILET and RTCRC since 1990, 1441 accessions were collected from various
regions of Indonesia. The focus of conservation is on the landrace or variety grown
by farmers over a long period of time. An overview of the accumulated collection is
presented in Table 1. Fig. 1 indicates the areas covered by the expedition team. Accessions
were obtained through collecting trips to the main production areas; for convenience
they will be referred to as Indonesian germplasm, not including the accessions collected
in Irian Jaya. During the expeditions to Irian Jaya, the interdisciplinary team also
recorded farmers’ knowledge related to these accessions (Schneider et al. 1993)
All accessions are maintained at Bogor (200 m asl) for Indonesian/Muara germplasm
(485 accessions), at RIV Lembang (1250 m asl) for Irian Jaya germplasm (566 accessions)
and another back-up of Indonesian germplasm (485 accessions). All accessions from
Irian Jaya were transferred to RILET for conservation in the field. A set of core collection
of Irian germplasm was re-introduced to Anggi under the care of RTCRC.
Table 1. Number of sweetpotato accessions collected in Indonesia and presently maintained
Province of origin
Acc-collected
Duplicated
Maintaining
Java
346
136
210
Sumatera
274
121
153
Kalimantan
0
0
0
Sulawesi
61
20
41
Bali,Nusa Tenggara
113
17
96
Irian Jaya
499 (+148)
65
419 (+147)
Total
1441
372
1046
Note: after eliminating at the Muara GP
40 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Fig. 1 Sites of collecting sweetpotato germplasm in Indonesia
Characterization
Morphological characterization has been carried out for all accessions maintained in
our collections. Observation was made 90 days after planting. The method of
morphological characterization was described by CIP, AVRDC and IBPGR (1991). The
descriptors present a system of prioritising characters. The colour chart developed at
CIP was used to record storage root skin and flesh colour. The characterization was
continued in the 3 to 5 seasons in the field where all accessions were planted in groups
according to the morphological characterization carried out in the previous season. The
grouping had resulted from a sorting of the data files according to the previous planting.
Accessions that resembled each other were planted side by side to facilitate further
comparison. Accessions with the same morphology were assigned a group number.
Field resistance to scab and flowering intensity under field condition were also recorded.
Duplicates were first identified in the Indonesian germplasm and as indicated in Table
1, about 294 accessions of this collection were duplicates. Eliminating the duplicate accessions
in the Indonesian germplasm was carried out in 1997. There were not many duplicate
accessions in the Irian Jaya germplasm; it was known that only 65 accessions were duplicates.
Evaluation for dry matter content
The Muara and Irian Jaya germplasm have been harvested several times since their initial
collection. At Bogor, the materials were harvested five months after planting, while at
Lembang, harvesting took place six to seven months after planting. On harvesting, we first
selected accessions with high yield; only selected accessions were further measured for dry
matter content. The results of this process from two sets of germplasm are presented in
Table 2a. Most accessions selected had dry matter content in the range of 30–35%. Among
accessions in the two sets of germplasm, some clones had a dry matter content of about
40%, while producing reasonably high yield. These clones become important materials for
the breeding programmes. Many of the Irian accessions did not produce storage roots when
first planted at Lembang after their collection and more accessions started to produce storage
roots after 2 to 4 clonal generation. Accessions from Irian Jaya, generally lacked orange
flesh colour (Table 2d), there was a tendency that these accessions were also lacked
pigmentation on abaxial vein or main vein (Mok 1996).
Resistance to leaf scab
Field resistance to scab was assessed by scoring the symptoms on a scale from 0 (no
symptom) to 4 (severe infection). Observation for scab resistance was carried out seven
times, among 2 sets of germplasm, showed that the Irian germplasm was more resistant
to leaf scab than the Muara germplasm. It is highly probable that Irian farmers have
selected accessions since they are cultivating sweetpotato as staple and animal feed
41
in highland, where it rains throughout the year (about 1700–2000 mm). The result of
scab scoring was used for presentation in Table 2b.
The IK recorded during the collecting expedition indicated that farmers in Irian Jaya are
using some sweetpotato varieties for baby food, general human consumption and feed for pigs.
Flowering ability
There was no difference in intensity and frequency distribution between the two groups
of germplasm. The result of flowering observation is presented in Table 2c; 40% of
accessions collected did not flower under natural conditions. Although only 12%
flowered profusely, almost 60% of accessions flowered to a larger or lesser degree. The
intensity of flowering depended very much on the genotype, which was another excellent
indicator for duplicate identification, in addition to morphological characterization.
Table 2. Frequency distribution of important characteristics of Muara and Irian Jaya sweetpotato
germplasm
a) Dry matter content of clones selected based on yield
Muara germplasm
Irian Jaya germplasm
DM (%)
Freq
Freq
Freq
Freq
Freq
Freq
Freq
Freq
Freq
Freq
Sep ‘96 Jun ‘97 Apr ‘98 Oct ‘98 Oct‘99 Jun ‘96 Dec ‘96 Jun ‘97 Jun ‘98 Jul ‘99
£ 20.0
0
1
0
0
1
1
1
0
1
1
20.1–25.0
3
4
9
6
3
1
1
0
0
0
25.1–30.0
17
15
40
45
20
15
19
1
4
8
30.1–35.0
13
11
29
26
20
26
59
16
24
24
35.1–40.0
3
5
5
6
3
9
22
20
6
4
≥ 40.1
0
0
0
0
0
0
0
5
0
0
Total
36
36
83
83
47
52
102
42
37
37
b) Resistance to scab disease
Score
Definition
0
1
No symptom
1–5 stem infected in a plot of
20 plants
Many plants infected slightly
(5–10% of leaf area)
All plants infected moderately
(11–25% of leaf area)
All plants infected severely
(>25% of leaf area)
2
3
4
Reaction
Highly resistant (HR)
Resistant ®
Moderately
resistant (MR)
Susceptible (S)
Highly
susceptible (HS)
Frequency
Muara GP+
Irian GP++
125
301
45
61
87
12
104
6
118
1
Total
479
381
The maximum value of scab resistance from seven observation between February–May 1991
++
From the observation 12 July 1995.
+
c) Flowering intensity
Frequency
+
++
Muara GP
Irian Jaya GP
0
No flowering
204
148
1
1–3 plants flowering within a plot of 20 plants
117
58
2
Most of plants with 1–3 flower
93
49
3
Most of plants with 4–7 flower
44
45
4
All plants flowering profusely
21
81
Total
479
381
+
The maximum value of flowering from seven observations between February–May 1991.
++
From the observation on July 12, 1995.
Score
Definition
42 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
d) Storage root flesh colour, predominant colour
Score
0
1
2
3
4
5
6
7
8
9
Total
Definition
No flowering
White
Cream
Dark cream
Pale yellow
Dark yellow
Pale orange
Intermediate orange
Dark orange
Strongly pigmented with anthocyanins
Frequency
Muara GP
Irian Jaya GP
204
148
202
27
85
176
0
26
99
87
18
41
34
6
31
3
12
1
5
6
486
373
Conservation
For conservation, accessions most frequently utilized in the breeding programme from
the two groups of germplasm are maintained in the RIV station, Lembang (1250 m asl),
and at Bogor (200 m asl). They would be constantly evaluated and utilized. They were
usually re-established twice a year, using cuttings obtained directly from the old field.
Since 1998, all accessions from Irian Jaya have been transferred to RILET for conservation
in the field genebank. A set of core collection of Irian germplasm was re-introduced
to Anggi under the care of RTCRC.
Botanical seeds have been collected from the field genebank, through polycross and
controlled pollination. Accessions were divided into several subsets based on the
previous field evaluation data, for example subsets of high yield, high dry matter content,
scab resistance, dark flesh colour, good flowering, high combining ability. In 1994,
through collaborative activities of RIFCB and The Ornamental Institute at Cipanas, a
large amount of seed families were collected for further selection in the breeding
programme (Table 3).
Table 3. Seeds obtained with polycross from germplasm and the ESEAP breeding programme
‘92–1995
1996
1997
1998
1999
Group
Total
Seeds
Seeds
Seeds
Seeds
Seeds
High DM
1 764 106 640
31 294
74 863
74 395
287 956
High DM and Yield
134 541
134 541
Scab resistance
17 756
7 207
25 115
High Pigmentation
27 923
102 573
130 496
High Altitude adaptation
46 143
46 143
High yielding capacity
2 952
23 300
26 252
High specific combining
15 246
148 790
64 036
ability
High frequency selection
31 300
31 300
of dry matter
Drought tolerance
454
454
Weevil resistance
19 357
19 357
Earliness
41 228
41 228
Germplasm
38 882
32 221
24 420
71 103
Multiplication plot
56 197
56 197
Total
104 999 164 266 224 858 265 310 298 813 1 977 781
43
Evaluation
We found that many accessions from Muara and Irian Jaya have reasonably high yield.
Each season, accessions were first selected by yield and then by dry matter content.
These accessions were not of extremely high dry matter content, but they demonstrated
a good yield potential in Indonesia. The accessions in Tables 4a and 4b were selected
based on their performance for at least two seasons. The accessions W0387 (Kambani),
W0345 (Iloka), W0139 (Toweko), W0116 (Helalekue), W0446 (Waimunki), W0331 (Kinta),
W0200 (Here-here), W0223 (Umakmbi), W0046 (Gelanggel), W0195 (Ketelale), B0097
(Biru), W0126 (Kali urang), B0160 (Unknown), S0068 (Unknown), B0367 (Unknown),
S0034 (Unknown) and S0083 (Gowi Raha) were constantly high in yield and dry matter
content over 2–5 seasons. These accessions have an advantage in selecting local varieties
for processing.
Table 4a. Accessions selected from Irian Jaya germplasm for high dry matter content and
high yield potential
Total
Yield
% DM
AverageAcc No
Variety
Jul ’99
DM (%)
-1
(t ha ) Jun ’96 Jul ’97 Dec ’97 Jun ’98 Jul ’99
W0387
Kambani
22.7
28.9
33.0
32.6
34.9
32.3
W0345
Iloka
16.6
33.8
33.8
34.8
34.1
W0139
Toweko
14.8
37.1
34.0
37.5
36.2
W0116
Helaleke
14.2
39.3
41.3
37.4
39.3
W0446
Waimunki
13.9
32.4
37.1
31.8
34.6
32.7
33.7
W0331
Kinta
13.4
34.4
35.5
33.6
34.1
36.0
34.7
W0200
Here-here
12.8
36.0
33.0
31.6
33.5
W0223
Umakmbi
11.8
41.0
34.6
39.0
38.2
W0046
Gelonggel
11.5
34.9
39.3
35.3
34.1
35.9
W0195
Ketelale
11.9
38.0
32.4
29.5
30.6
32.6
Table 4b. Accessions selected from Muara germplasm for high dry matter content and high
yield potential
Total
Yield
% DM
AverageAcc No
Variety
Jul ’99
DM (%)
(t ha)
Sep ’96 Jun ’97 Sep ’97 Jun ’98 Oct ’99
B0097
Biru
23.0
36.6
36.0
26.5
31.6
32.6
B0126
Kali Urang
24.7
36.6
25.9
25.5
29.3
B0160
Unknown
18.2
34.0
29.2
32.1
30.4
31.4
S0068
Unknown
17.7
30.4
25.6
31.4
29.1
B0367
Unknown
15.5
32.1
34.3
30.3
32.2
S0034
Unknown
22.6
31.6
26.2
26.5
32.8
29.3
S0083
Gowi Raha
24.6
27.3
29.0
36.8
24.9
29.5
Documentation
CIP-ESEAP uses the following definitions in genetic resources documentation, which
were stored in a computerized d-base: Passport accession data file, Passport seeds data
file, Characterization data file, and Digital image of leaf, stem, and storage roots. These
individual files were linked and it becomes thus possible to select accession for any
combination of desired data. It is also useful in judging the worth of a variety to assess
the agronomic and utilization potential of an accession.
44 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Sweetpotato breeding for high dry matter content
Increasing dry matter content is the primary objective for the sweetpotato breeding
programme in the ESEAP region. Since 1990, a large number of CIP pathogen tested
clones have been evaluated in Bogor and at other sites in Indonesia. However, they
have low dry matter content or poor adaptability, but good agronomic characters. We
are now combining this CIP germplasm with locally important cultivars in a recurrent
selection scheme for long-term population improvement.
Botanical seeds introduced from various sources, including CIP headquarters, other
regional breeding programmes, China, Japan, and the Philippines have been intensively
evaluated and selected (Table 5). From 1993 to 1995, about 90 advanced breeding clones
were selected for high DM content, and high yield in Bogor. These clones were again
evaluated at Lembang and Malang to select the most suitable varieties for starch
production. As a result, there are about 20 advanced breeding clones (Table 7). The
advanced breeding clones also have many useful traits such as resistance to scab, white
or cream flesh colour, and good root shape. The most promising advanced breeding
clones are listed in Table 6. They have stable yield in different environments, high dry
matter content, and resistance to scab.
Based on overall performance, the four best clones were selected for starch
processing, i.e. AB94001.8 (CIP-2), a selection from Japanese seed families, and the other
three clones from CIP-HQ. All clones are high yielding and high in DM and starch
contents. These advanced breeding clones have been distributed to many farmers,
institutes, NGOs and private companies in Indonesia.
Table 5. Origin of advanced breeding clones selected at Bogor in 1993–95. All materials were
initially introduced as botanical seed
Source
Advanced breeding clones
Families evaluated
selected from the source
at Bogor
AVRDC
1
42
XSPRC, GAAS, China
16
62
NARC, Japan
31
15
Philippines (ASPRAD)
1
53
MSU, USA
0
18
CIP-HQ
37
63
CIP-SSA
5
38
CIP-ESEAP
4
78
CIP-SWA
0
5
Total
95
374
Table 6a. Best clones selected for high dry matter content and yield
Starch
Yield t/ha
Dry matter content %
Skin
Clone
content %
colour
Malang Bogor Lembang Malang Bogor Lembang Lembang
B94001.8
30.4 14.1
25.9
37.8 34.8
37.1
25.4
Cream
AB94065.4
27.5 15.6
24.3
37.2 37.3
33.8
0.0
Cream
AB94078.1
26.2 18.5
18.4
39.4 40.4
36.7
25.1
Red
AB94079.1
28.6 14.8
17.9
38.7 38.8
36.0
27.0
Cream
Top
Flesh
weight
colour
t/ha
White 35.0
White 29.4
White 14.4
White 27.8
45
Table 6b. Starch productivity at Lembang and Malang
Clone
Yield at
Yield at
Starch
Lembang
Malang
content
t/ha
t/ha
%
AB94001.8
25.9
30.4
25.4
AB94065.4
24.3
27.5
–
AB94078.1
18.4
26.2
25.1
AB94079.1
17.9
28.6
27.0
Table 6c. Origins of selected clone
Clone
Source
AB94001.8
Japan
AB94065.4
CIP 194064
AB94078.1
CIP 194101
AB94079.1
CIP 193005
Starch
production at
Lembang t/ha
6.58
–
4.62
4.83
Female
Kusyu 102
PRMG 1-003
JPKY 2-019
JPKY 7-014
Starch
production at
Malang t/ha
7.72
–
6.58
7.72
Male
Kanto 106
PC9302 REND.MS
OP9301 PC93
OP9301 PC93
Table 7. Clones selected for overall average performances with high dry matter and high yielding
potential at different environment
No Clone
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
AB95012.4
AB94065.6
AB94065.10
BB93521.5
AB95007.2
AB94078.1
AB94065.9
AB94065.1
AB94001.8
AB95108.3
AB94079.1
BB94572.2
AB95012.3
AB94065.5
AB95008.3
AB94065.7
AB94080.3
AB94085.5
AB94065.8
AB94079.6
AB95002.6
AB95002.7
AB95002.3
AB94065.2
AB94065.4
DM%
Bogor Lembang Malang
Sep
Apr
Aug
34.4
34.2
30.4
38.8
38.4
32.8
34.1
37.2
30.9
26.8
31.3
30.4
31.7
33.6
30.0
35.2
38.9
33.9
34.2
39.1
33.0
36.5
36.8
35.6
34.8
39.2
33.0
32.7
36.5
32.3
35.2
35.2
34.3
35.7
37.0
34.8
36.0
35.7
32.5
34.2
36.6
34.0
34.6
33.6
33.7
32.5
35.1
34.3
36.3
38.2
35.0
33.8
39.9
36.0
32.0
34.0
31.5
38.4
37.3
35.9
33.0
38.5
34.6
35.0
37.9
33.1
34.5
36.8
33.6
31.8
37.6
30.9
30.9
35.4
30.7
DM
Ave
33.0
36.7
34.1
29.5
31.8
36.0
35.4
36.3
35.7
33.8
34.9
35.8
34.7
34.9
34.0
34.0
36.5
36.5
32.5
37.2
35.4
35.3
35.0
33.4
32.3
Yield t/ha
Bogor Lembang Malang
Sep
Apr
Aug
20.0
31.4
11.6
18.6
32.2
8.5
21.2
26.8
11.0
19.5
29.6
8.9
17.1
31.4
8.7
19.0
26.4
10.1
16.0
32.7
6.7
16.7
30.9
6.2
15.0
25.9
12.6
13.6
31.0
8.8
10.2
32.4
10.3
13.3
29.3
8.7
12.0
31.1
6.4
15.1
27.4
6.1
11.6
27.4
8.7
10.7
25.1
8.8
10.5
24.0
6.0
13.2
21.0
4.0
13.6
18.6
5.7
10.8
20.0
6.9
4.0
26.7
6.7
1.4
28.1
6.7
8.6
21.4
5.9
8.2
22.8
4.5
6.0
22.2
4.0
Yield
Ave
21.0
19.8
19.7
19.3
19.1
18.5
18.5
17.9
17.8
17.8
17.6
17.1
16.5
16.2
15.9
14.9
13.5
12.7
12.6
12.6
12.5
12.0
12.0
11.8
10.7
Shape
Skin
Good
Good
Round-oval
Small
Oval
Long
Round
Long
Thin-small
Small
Big-round
Medium
Large-oval
Long-oval
Medium-oval
Round
Oval
Long-oval
Round
Round
Oval
Oval
Oval
Oval
Long-oval
L.yellow
Yellow
Cream
Red
Cream
Red
L.yellow
L.yellow
Red
Red
Cream
L.yellow
Red
Red
Yellow
Pink
Yellow
L.yellow
Red
Pink
Red
Cream
Red
Red
Red
Evaluated in Bogor-Lembang, and Malang in September, June–September 1999 (Bogor), November
1997–April 1998 (Lembang), April–August 1998(Malang)
46 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
On-going trials
In the ESEAP region, there are several on-going trials. The trials are conducted at three
environments, i.e. poor soil in humid tropics (Bogor), 200 m asl; cooler climate in
highland (Lembang), 1200 m asl; and high fertile soil (Malang), 500 m asl. The entries
used in these trials were generated through polycross. The maternal parent came from
germplasm which were sorted based on their specific character, flesh colour, high dry
matter content and yield potential. The accessions are used as maternal parent to produce
botanical seeds (Table 8).
Table 8. The accessions used as maternal parents in polycross
ACC-No
Variety
Source
B0571
Unknown
OP of Indonesia germplasm
B0572
Muntul IR
OP of Indonesia germplasm
B0191
Keduk
OP of Indonesia germplasm
B0068
SQ-27
OP of Indonesia germplasm
W0232
Karubaka
OP of Irian Jaya germplasm
B0381
Unknown
OP of Indonesia germplasm
W0185
Ekenhili
OP of Irian Jaya germplasm
W0228
Yoban
OP of Irian Jaya germplasm
W0100
Ndulanom
OP of Irian Jaya germplasm
W0124
Korwambi
OP of Irian Jaya germplasm
B0126
Kali Urang
OP of Indonesia germplasm
B0107
Dayak
OP of Indonesia germplasm
S0221
Unknown
OP of Indonesia germplasm
W0152
Yuaiken
OP of Irian Jaya germplasm
Potential characters
Earliness
Earliness
Earliness
High dry matter content
Dark flesh colour
Dark flesh colour
Dark flesh colour
High dry matter content
Dark flesh colour
Dark flesh colour
High dry matter content
High dry matter content
Dark flesh colour
Dark flesh colour
Future plans
•
•
•
Continuing to conserve the botanical seeds in the polycross, the accessions can be
divided, based on current specific usage, high vigour, yield, earliness, drought
tolerance and table consumption.
Transferring the responsibility of further conservation of the germplasm to the care
of the Indonesian institutions working on sweetpotato: RILET, RIFCB and RCTRC.
Publication and distribution of germplasm, and the advanced breeding clones
through the internet and brochures.
References
CIP, AVRDC and IBPGR. 1991. Descriptors for sweetpotato (Z. Huaman, ed.). IBPGR,
Rome.
Mok, I.G. Sweetpotato Germplasm Conservation in ESEAP in Progress Report 1999.
ESEAP-Sweetpotato Breeding. Bogor, Indonesia.
Schneider, J., C. A. Widyastuti and M. Djazuli (eds.). 1993. Sweetpotato in the Baleim
Valley area, Irian Jaya. A report on collection on study of sweetpotato germplasm,
April–May 1993. CIP and RTCRC. 54p.
47
Recent Progress on the Conservation and Use of Sweetpotato in
the Philippines
Algerico M. Mariscal, Jose L. Bacusmo, Villaluz Z. Acedo and Enrique Abogadie
Philippine Rootcrop Research and Training Centre, VISCA, Leyte, Philippines
Introduction
Sweetpotato ranks second to cassava among rootcrops in the country in terms of area
and production. For the last 10 years, the average area planted with sweetpotato is
144 300 ha, with mean production of 689 100 metric tons. It is generally grown in marginal
and harsh environments and adapted to several cropping systems. Generally,
sweetpotato is widely grown by subsistence and commercial farmers in all agroecological conditions.
Ninety percent (90%) of the total production of sweetpotato is consumed as food
and ten percent (10%) are utilized for feed, starch and waste. Recent developments have
favoured the utilization of sweetpotato for animal feed and starch.
The sweetpotato genetic resources in the country are diverse. Farmers’ varieties as
well as introduced and recommended varieties are now grown in the countryside.
However, with natural calamities, such as long dry spells, heavy rains and typhoons,
it is inevitable that some of the genetic resources become extinct or go missing, resulting
in genetic erosion of sweetpotato genetic resources in the country. As such, concerned
government agencies have collected and maintained sweetpotato genetic resources in
the field genebanks and in the laboratory in the form of tissue culture for conservation
and use. The largest genebank of sweetpotato is located at the Philippine Rootcrop
Research and Training Centre (PRCRTC) at the Visayas State College of Agriculture
(ViSCA), Baybay, Leyte. Other agencies that maintain sweetpotato genetic resources
are the Institute of Plant Breeding (IPB) of the University of the Philippines at Los Baños
(UPLB), College, Laguna, and the Northern Philippine Rootcrop Research and Training
Centre (NPRCRTC) of Benguet State University in La Trinidad, Benguet.(Bacusmo et
al. 1995)
Status of sweetpotato conservation
Three years ago (May 1996), participants from 11 countries in Asia gathered together
in Bogor, Indonesia, through the efforts of CIP and IPGRI in order to discuss vital issues
on the conservation of sweetpotato genetic resources and this led to the formation of
a sweetpotato network. With collective effort and a common desire, the Asian Network
for Sweetpotato Genetic Resources (ANSWER) was founded during that meeting. The
first major activity of the network was the “ANSWER training course on maintenance,
characterization, and duplicate identification of Ipomoea batatas collection” held at
PRCRTC, ViSCA, Baybay, Leyte, during September 1–6, 1997. Six ANSWER member
countries (Philippines, Japan, Indonesia, Malaysia, Vietnam and Thailand) participated
in the course and the expertise was provided by CIP/IPGRI. Other member countries
could not participate due to communication and travel processing problems. During
the training, practicum on the morphological characterization based on CIP/IPGRI
descriptors list was undertaken including its subsequent statistical analysis for duplicate
identification. Each participating country was expected to apply the knowledge learnt
at the course for characterization and duplicate identification of their respective
sweetpotato genetic resources collections. Using such a procedure, the following is the
current status of sweetpotato genetic resources in the country.
48 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Current number of clonal accessions maintained in field genebank
In 1996, the total number of sweetpotato collections in the Philippines reached up to
2855 (Table 1), the majority of which are conserved in PRCRTC. After the ANSWER
training, the accessions were subjected to morphological characterization and the
available materials are only 1815 accessions. In PRCRTC, the reduction of number from
1402 to 931 is attributed to severe environmental stresses, like long dry periods, heavy
rains, pests and diseases. Losses were observed in the field genebank through continuous
replanting. In NPRCRTC of Benguet, the reduction of number was due to the elimination
of duplicates by the curator based on CIP/IPGRI descriptors list. It was found that
the majority of the accessions were duplicates. In IPB and UPLB, no figure for recent
sweetpotato accession was provided.
Table 1. Total number of sweetpotato clonal accessions in the Philippines (1999)
Number of accessions
Agency
Collected
Available
Philippine Rootcrop Research and Training Centre,
1402
931
ViSCA, Baybay, Leyte
Northern Philippine Rootcrop Research And Training
653
105
Centre, BSU, La Trinidad, Benguet
Institute of Plant Breeding UPLB, College, Laguna
800
800*
Total collection
2885
1815
* No information as to the number of accessions available.
PRCRTC, IPB and NPRCRTC are still in the process of field evaluation of the
characterized accessions for further verification of duplicates. In PRCRTC, the
germplasm collection is composed of registered cultivars, native varieties, introduced
cultivars and hybrids (Table 2). Of a total of 1402 accessions, the registered cultivars
accounted for 1.5%, native varieties 80%, introduced cultivars 17% and hybrids 1.9%.
After these materials are fully characterized, it is expected that a large number of
duplicates may be identified.
Table 2. Breakdown of the number of germplasm
collection of PRCRTC (1999)
Source
1996
1999
Registered cultivars
19
21
Local cultivars
1118
904
Introduced cultivars
238
Hybrids
27
6
Total
1402
931
Current number of accessions with passport data and morphological
characterization
Of the total number of 1402 accessions from PRCRTC, 1258 have passport data and
these data have been submitted to CIP, Peru, for developing of the database. With the
use of CIP/IPGRI descriptors list, 550 accessions were thoroughly characterized and
all the morphological and agronomic data are available. Germplasm collections of
NPRCRTC and UPLB and passport data are not reported yet. Morphological
characterization and evaluation are still an on-going activity. (Mariscal 1998)
49
Number of accessions with evaluation data (yield, pest and disease)
As far as the evaluation is concerned, only 50% of the collections in PRCRTC were
previously evaluated for yield. Variation in yield ranged from 1 to 25 t/ha. Screening
for weevil and scab resistance and tolerance to acidic and shade conditions were also
done. Recently all the collections were planted in a single row at 10 plants per row
to further evaluate the agronomic characteristics of the collection aside from
morphological characterization for duplicates identification. The other agencies
maintaining collection may also do their respective evaluation, especially those, which
participated in the ANSWER training.
Number of accessions having farmers’ indigenous knowledge
On this aspect, not much work has been done at the centre. The Users’ Perspective
with Agricultural Research and Development (UPWARD) has studied and documented
farmers’ indigenous knowledge on sweetpotato variety identification and maintenance
in southern Mindanao (Piniero 1995). The study focused on “memory banking” and
“community-based genebanking”. This aspect needs to be worked out further in order
to utilize the farmers’ knowledge as complementary tool in genetic conservation in
farmers’ fields.
Number of accessions maintained in vitro
To back up field collection of important accessions, in vitro (tissue culture) maintenance
is done. Due to lack of financial support, only a very minimal number of accessions
were maintained in the laboratory. In 1995, the PRCRTC tissue culture laboratory
maintained 155 accessions (Table 3) broken down as follows: 9 registered cultivars, 64
CIP materials and 82 crosses from I. trifida x I. batatas. Lately, a number of CIP materials
and the hybrids were found missing due to contamination and death of plants upon
transfer to the greenhouse. Losses are also attributed to lack of funds. Recently, the
number of accessions maintained in vitro is only 82 but 37 farmers’ varieties are included
in vitro. At UPLB, 67 accessions are maintained in vitro.
A large proportion of field genebank collection is lost due to biotic and abiotic
stresses. It is necessary that, after thorough characterization and elimination of
duplicates, the important genetic materials are maintained in vitro.
Table 3. Total number of collections stored in vitro (1999)
Agency/source
1994
1999
PRCRTC
Registered cultivars
9
9
Farmer’s varieties
–
37
CIP materials
64
25
Introductions (Japan)
–
5
82
6
Hybrids (I. batatas x I. trifida)
Total for PRCRTC
155
82
IPB, UPLB
General collections
67
67*
Total accessions
222
149
* No new information about the actual number of accessions in vitro.
50 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Number of accessions having molecular fingerprints
This level of evaluation entails a large amount of money aside from needed equipment.
With a small support from IPGRI, a part of the farmers’ varieties collection (19 cultivars)
were sent to UPM, Malaysia, for DNA analysis in order to determine the level of diversity
of the farmers’ varieties at molecular level. Results of this study are awaited.
Documentation
At the start of massive collecting of sweetpotato germplasm, information on collected
materials was kept in paper files. It was only when the computer facilities became
available at the centre that passport data and morphological characterization data were
transferred to computerized databases. This was further strengthened after the ANSWER
training in last September of 1997 that demonstrated the software to handle database
on passport, morphological and evaluation data. All important information related to
germplasm collection, especially on agronomic evaluation, will be entered into computer
database. Another cycle of evaluation of all the germplasm collection will be undertaken
to determine the performance of the genetic materials under various conditions.
Utilization of germplasm collection
Success in the breeding programme depends on the wide genetic diversity in the
available genetic resources. Thus, the first major step in any breeding programme is
to assemble a diverse germplasm collection. Germplasm collection caters to two-fold
purposes, one for the preservation of genetic materials and the other for the development
of new improved varieties.
For more than 20 years of its existence, PRCRTC and its cooperating stations
developed 21 registered improved varieties by utilizing the available genetic materials.
Since the start of the breeding programme, 14% of the total germplasm collection were
used for the development of improved varieties.
The ex situ conserved materials also provided the needed farmers’ varieties in the
area where they are no longer available. This is manifested by some farmers in Lanao
del Norte who envisioned having the variety previously grown in their area but is no
longer available in that locality. Thus, with germplasm available, one can easily supply
the farmers the needed native varieties.
Field genebank management
All the sweetpotato collections of PRCRTC are presently maintained in 14-inch clay
pots, which are partially buried in the open field to allow irrigation. The accessions
are grouped together according to the shape and colour of the leaves. Each genotype
in the pot is renewed/replanted every 3 months. Aside from pots, separate single-row
plots per accessions are maintained in a separate field for evaluation and characterization
purposes. Additionally this serves as back up for pot maintenance. This procedure is
laborious, especially when a large number of accessions are maintained (Mariscal and
Lopez 1996)
In situ conservation has been identified to be a complementary method for longterm conservation. However, in a strict sense, this type is not applicable to sweetpotato
because this crop cannot survive in the field without human intervention. For this
purpose, on-farm conservation may still fall under in situ conservation. This method
was introduced in the southern Philippines by UPWARD (Prain and Piniero 1996).
Farmers themselves are the plant curators in their own fields. They are given the
materials, native as well improved, for them to maintain. In the beginning the project
51
was satisfactory, but as the cropping patterns in the area changed, coupled with social
problems, a number of germplasm materials were no longer available. However, when
the demand for the sweetpotato products is high, farmers tend to acquire genetic material
to maintain and plant. Thus, in situ/on-farm conservation should not be taken as an
independent entity but should be a complementary component in the overall germplasm
conservation effort.
An attempt to establish a core collection of sweetpotato was done with the help
of IPGRI. Three hundred accessions representing all parts of the collection site were
randomly taken and all the morphological data were gathered from the database.
Detailed analysis from this group will be made using available statistical tools. At the
moment this is to be pursued and studied carefully if this number truly represents the
entire germplasm collection in the country.
Because of the risk and labour of vegetative maintenance of sweetpotato germplasm,
IPGRI provided a small fund to study the possible production of a number of botanical
seeds per accession that would retain the maternal genetic composition. Initial results
revealed that, using low to high flowering accessions, selfed seeds were produced with
varying percentages. Offsprings obtained from the selfed seeds have greater percentage
of maternal traits as compared to offsprings from the open pollinated seeds. The result
needs to be further confirmed by additional studies because heavy rains affected the
evaluation phase of the offsprings from both self and open pollinations. From the initial
results, there seems to be an indication that botanical seed can be an additional way
of conserving sweetpotato genetic resources.
Problems and constraints of field genebank management
It is a common experience of all plant curators that the maintenance of vegetative
materials in the field is vulnerable to many stresses and results in loss of important
genetic materials. This is mainly because of the exposure of the plants to environmental
extremes. PRCRTC has been maintaining sweetpotato germplasm in the field for more
than 20 years and tremendous loss of genetic materials has been observed. In records,
PRCRTC recently has a total collection of 1402 accessions and the remaining available
clonal materials come to only 931, which include some duplicate accessions. Thus, aside
from the loss of the important materials, the costs of collecting as well as the maintenance
borne by the government and other funding agencies are wasted. Field genebank
management therefore, has the following problems:
1. High cost of maintenance
2. Biotic stress (pests and diseases) and abiotic stress (droughts, typhoons, sociopolitical factors, and economic factors)
3. Duplicates are still maintained, thus maintaining large collection
4. Genetic integrity of the accessions has not been ascertained
5. Lack of financial support.
Ways to overcome constraints in field genebank management
Due to several problems encountered in field genebank maintenance, an alternative
conservation strategy is needed. These are the following:
1. In vitro maintenance – Materials that are already characterized and ascertained as
being different from each other shall be put in in vitro culture. In this case a tissue
culture laboratory able to handle the materials is needed. PRCRTC, after thoroughly
characterizing the collections and ensuring that duplicates are already eliminated,
shall maintain important collections in vitro.
52 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
2. On-farm conservation (in situ) – In areas where indigenous varieties are maintained
by farmers, they shall be tapped and given recognition and be backed up by ex
situ conservation. This is a complementary strategy of genetic conservation.
3. The use of botanical seed – Conservation by seed seems to be very convenient to
handle and to process sweetpotato germplasm resources. An intensive study on this
aspect is needed considering the high ploidy level of sweetpotato.
Possible contributions from the network to overcome constraints
Considering that the network is a group of people or organizations that agree to share
information or other resources in such a way that greater benefit is derived, the network
can have the following contributions:
1. Sharing of information related to field genebank management
2. Training on field genebank management
3. Safety duplications
4. Creation of regional genebank
5. Germplasm exchange
6. Clean up of materials.
Recommendations
To have a dynamic germplasm collection for food security, the following are
recommended:
1. Germplasm maintenance shall be fully supported by the government in financial
and policy matters
2. The collections shall be fully characterized and only different morphotypes
maintained
3. Training shall be provided and core collections developed
4. Important genetic materials shall be placed in vitro for long term conservation
5. Study shall be made on the possibility of conserving botanical seed
6. Genetic materials shall be cleaned up
7. Technical backstopping from CIP/IPGRI shall be given
8. Exchange of germplasm shall be facilitated.
References
Bacusmo, J.L., V.Z. Acedo, A.M. Mariscal and M.Z. Oracion. 1995. Sweetpotato genetic
resources in the Philippines. Pp. 105–114 in Root and Tuber Crops. Proceedings of an
International Workshop of Genetic Resources. Tsukuba, Japan. March 15–17 1994.
Mariscal, A.M. 1998. Sweetpotato breeding and genetic resources conservation in the
Philippines. Pp. 99–118 in Sweetpotato Genetic Resources Conservation and Use
in Asia (R.T. Sanico, ed). Proceedings of the MAFF/PRCRTC International
Workshop. Baybay, Leyte, Philippines. MAFF, Japan
Mariscal, A.M. and E.L. Lopez. 1996. The utilization of Asian sweetpotato biodiversity
in breeding in the Philippines. Pp. 27–34 in Proceedings of the Workshop on the
Formation of a Network for the Conservation of Sweetpotato Biodiversity in Asia.
Bogor, Indonesia. 1–5 May 1996 (V. Ramanatha Rao, ed.). IPGRI-APO, Singapore.
Piniero, M. 1995. Methodologies for documenting user ’s indigenous knowledge in
sweetpotato varieties and conservation of rootcrop genetic resources. Pp. 27–33 in
Indigenous Knowledge in Conservation of Crop Genetic Resources. Proceedings
of an international workshop. Bogor, Indonesia. Jan. 30–Feb. 3, 1995 (Schneider,
ed.). CIP-ESEAP, Bogor, Indonesia.
Prain, G. and M. Piniero. 1996. Communities as Curators of Plant Genetic Resources.
The Case of Rootcrop Conservation in the Philippines. IDRC-UPWARD Project.
53
Conservation and Use of Sweetpotato in Thailand
Narin Poolperm
Phichit Horticultural Research Centre, Department of Agriculture, Phichit, 66000,
Thailand
Introduction
Sweetpotato is an important food crop, ranking third after cassava and potato in
Thailand. It is grown all over the country. The planting area of sweetpotato increased
from 6530 ha in 1996 to 8580 ha in 1998. The average production was 15.5 t/ha. About
95% of the production was for human food as desserts, snacks and main dishes and
5% for animal feed.
Status of sweetpotato germplasm
The collecting and conservation of sweetpotato germplasm are undertaken by
government agencies while farmers conserve them on farms by growing them
continuously. Many accessions have been collected and are conserved in the government
agencies but a few farmers’ cultivars are yet to be collected. One of the government
agencies is Phichit Horticultural Research Centre, Department of Agriculture. It is in
the lower north of Thailand and 350 km from Bangkok. By 1999, Phichit Horticultural
Research Centre had collected 365 accessions of sweetpotato, of which 47 accessions
were native cultivars, 35 introduced, 275 breeding lines and 8 released varieties.
ANSWER Network
Germplasm conservation of sweetpotato in Thailand
Germplasm conservation in the field
Germplasm conservation in the field is the most practical method and can be divided
into two types.
Ex situ maintenance is done in Phichit Horticultural Research Centre, by planting
sweetpotato in plots of 1x3 m with 30x100 cm spacing. Ten cuttings are planted in each
plot. Harvesting is done after four months. Screening for pest and disease resistance
and determination of quality are carried out by using five plants per plot. The other
five plants are used as source of apical cuttings for replanting in the new location every
five months. Fertilizer application and chemical spraying are carried out as needed.
In situ germplasm maintenance is done in the farmers’ fields, especially of those
cultivars grown for commercial purposes. The farmers’ expertise is considerable on
cultivars that are part of their everyday work. They select sweetpotato types themselves
by using criteria such as the market requirements and their preferences. Each farmer
conserves 1–3 accessions, which are either landraces or promising accessions. The
farmers consume or sell the storage roots, and maintain small plots of 4x6 m near their
homes or water resources as a source of propagules. Each accession has 2–5 plots.
Fertilizer application and chemical spraying for pests and diseases are done occasionally.
At the onset commercial sweetpotato fields range in size from 0.5 to 5 ha.
54 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Conservation as botanical seeds
This form of conservation started in Thailand in 1997 after the 1996 workshop on
sweetpotato by CIP and IPGRI in Bogor, Indonesia, by using the seeds from open
pollination of rarely used and flowering cultivars. Healthy seeds from the same clones
or the same plants are kept at 5% moisture content in foil packets, labelled with name,
location and date, and then kept in a temperature controlled room of 5 ˚C. Botanical
seeds of 50 accessions were conserved at Phichit Horticultural Research Centre in 1999.
Other conservation methods, such as the storage of roots and in vitro maintenance,
are not used in Thailand because of the high cost. It is hoped that an in vitro conservation
method will be developed to safeguard important accessions from the risk of diseases
and other damages. In vitro method is still the best way for many countries to exchange
germplasm.
Problems of sweetpotato germplasm conservation
Lack of financial support:
Thailand gives priority to field crop and fruit research. Sweetpotato is nearly at the
end of the national priority ranking, after rice, sugar cane, fruits and other crops.
Researchers have to do research on these priority species before undertaking any research
on sweetpotato.
High cost of large field collection:
Large field collections are costly and affected by maintenance problems such as the
occurrences of pests, droughts and floods.
Problem solving methods
Minimize the conservation
It is an improvement to keep the number of germplasm accessions to the minimum
to reduce costs. This can be done by eliminating duplicate accessions and undesirable
breeding lines such as the lines that have no resistance to pests, are low yielding, and
of poor quality or late maturing.
Minimize plot size
Before the meeting of the ANSWER Network in 1996, the plot size of sweetpotato in
the conservation field consisted of 1x6 m plots with 20 plants per plot. After the meeting,
the plot size was reduced to 1x3 m, with 10 plants per plot and turning the vine every
month.
Additionally, the method of conservation of seeds of rarely used and flowering
accessions was instituted.
• Encourage farmers to grow their preferred accessions for home consumption and
to grow promising accessions of the government for commerce, and maintain
sweetpotato germplasm at the farm.
• Resort to use other financial resources to support conservation activities. Many
research projects are done on chilli, taro, bamboo shoots and jackfruit. Some resources
from these projects, such as materials and labour, are used in sweetpotato germplasm
conservation.
55
Current number of clonal accessions as compared with that of the last 3 years (19961998)
Phichit Horticultural Research Centre collected and conserved about 2979 accessions
of native cultivars, and introduced cultivars, breeding lines and released varieties in
1996. The duplicate accessions were eliminated; the number of accessions collected and
conserved decreased to 1500 in 1997, to 750 in 1998 and to 365 in 1999. The duplicate
accessions of native cultivars were reduced to 47 in 1999. About 35 accessions that were
either late maturing, or low yielding, or non-resistant to pests or introductions that
were not required for the market were eliminated in 1999. About 275 breeding lines
from Phichit Horticultural Research Centre and introduced ones from SAPPRAD and
CIP with similar characteristics were also eliminated. Farmers were encouraged to grow
for commerce eight released varieties from breeding or introduced cultivars that were
of high yield, good quality as per the requirement of the market, resistant to pests and
early maturing (Table 1).
Table 1. Number of sweetpotato accessions conserved in
Thailand from 1996 to1999
Number of accessions
Source
1996
1997
1998
1999
Native cultivars
25
25
27
47
Introduced cultivars
64
35
35
35
Breeding lines
2885
1435
682
275
Released varieties
4
5
6
8
Total
2979
1500
750
365
Percentage of total holding of native and introduced cultivars, breeding lines and
released varieties
In 1999, Phichit Horticultural Research Centre collected and conserved 47 native cultivars
(12.9%), 35 introduced cultivars (9.6%), 275 breeding lines (75.3%) and 8 released varieties
(2.2%).
Number of clonal accessions for which botanical seeds are available
After the workshop on sweetpotato in Bogor, Indonesia, in 1996, Phichit Horticultural
Research Centre conducted research on the collecting and conservation of sweetpotato
by botanical seeds produced by open pollination. Fifty rarely used and flowering
accessions are kept in foil packets in the cold room.
Number of clonal accessions for which passport data are available
Passport data as per the CIP/IPGRI descriptors are available on 47 native cultivars,
35 introductions, 275 breeding lines and 8 released accessions.
Number of accessions for which farmers knowledge is available
Eighteen farmer preferred accessions of sweetpotato are collected and conserved at
Phichit Horticultural Research Centre. These collections are from ten native sources,
viz. Maejo, E-ka, Nigro, Mankaset, MankaiSukhothai, Mantophuck Rayong, Man Chan,
Mankaset Nakorn, Khaobaipho and Manphuang, and eight promising accessions, viz.
Phichit 1, PIS 115-1, PIS 113-7, PIS 091, PIS 117-5, PIS 94-1, T101 and CIP–14-1.
56 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Number of accessions for which morphological and agronomic characterization data
and further evaluation data are available
After the workshop on sweetpotato at CIP, Bogor, Indonesia, in 1996 and the training
of sweetpotato scientists at PRCRTC, Philippines, in 1997, Phichit Horticultural Research
Centre has carried out characterization as per agreed descriptors. All the 47 native
cultivars, 35 introduced cultivars, 275 breeding lines and 8 released varieties have been
characterized.
Molecular fingerprinting
Molecular fingerprinting of sweetpotato accessions is not done because of budget
limitations. CIP and IPGRI are encouraged to collect and conserve the important
sweetpotato accessions or released varieties from each country in the ANSWER network
and study molecular fingerprints of them.
Future plans
•
•
•
•
•
Phichit Horticultural Research Centre (PHRC) will continue to collect and conserve
sweetpotato germplasm by increasing maintenance of botanical seeds and promoting
sweetpotato germplasm conservation by farmers in every region of the country.
PHRC will develop improved sweetpotato cultivars by using the collected sweetpotato
germplasm for fresh consumption and processing and for better sweetpotato.
PHRC will exchange sweetpotato cultivars among the countries in Asia and Oceania.
CIP and IPGRI should support a budget for the collecting and conservation of
sweetpotato, especially the best, promising or recommended cultivars of each country
for in vitro propagation and exchange of cultivars among the countries. The countries
in ANSWER may take the interesting sweetpotato cultivars to evaluate in their
locations.
CIP and IPGRI should print newsletters about sweetpotato researches from ANSWER
countries or others to assist sweetpotato collection and conservation in the future.
Conclusion
Although sweetpotato is not a staple food of Thailand, it is of local importance as food
and a source of income. Collection and conservation of sweetpotato germplasm are
necessary for breeding to get new varieties with high yield and good quality as required
by markets, resistance to pests and diseases and early maturity. Sweetpotato conservation
in Thailand is of two types: conservation in the field and conservation of botanical seeds.
However, the problems of conservation are the lack of funds, high costs and the
environmental risks. Plot size reduction in field conservation, botanical seed
conservation, and the promotion of on-farm sweetpotato conservation make sweetpotato
conservation more efficient. In 1999, research on sweetpotato conservation involved
365 accessions of native cultivars, breeding lines and released varieties.
CIP and IPGRI are encouraged to support sweetpotato conservation and to provide
in vitro back-up storage, especially for good quality sweetpotato accessions from each
country and promote exchange of germplasm for the people in Asia and Oceania.
57
Fig. 1 Sweetpotato collection in the field genebank at Phichit Research
Horticultural Research Centre (spacing 1.5x1.5 m)
Fig. 2 Roots of promising cultivar PIS 115-1 that matures in 90 days
58 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Status of Conservation and Use of Sweetpotato Germplasm in
Vietnam
Luu Ngoc Trinh, Bui Tuyet Mai and Nguyen Ngoc Hue
Genetic Resources Centre, VASI, Vietnam
Introduction
In Vietnam, sweetpotato takes the third place of importance in the rank of food crops
after rice and corn. This crop has traditionally been an important food of Vietnamese
farmers and a principal one for those living in coastal areas with prevalence of sandy
soils and in midland areas with degraded soils, where there is no cultivation of rice.
In Vietnam sweetpotato is cultivated in the spring crop season in a double crop
farming system characterized by an upland crop in the dry season and summer rice
in the wet season. It is well known that North Vietnam has cold winters. Since the early
1970s, sweetpotato has extended in North Vietnam as a winter crop in irrigated areas.
This is a new cropping season, which has helped to establish a farming system of three
crops per year with rice or an upland crop in spring or spring-summer season, rice
in summer or summer-autumn season and an upland crop in autumn-winter or winter
season. Since the establishment of this new cropping system, sweetpotato has been
cultivated in the winter season, which requires cold tolerant varieties.
Sweetpotato is an extensive and highly sustainable crop. One can find it cultivated
in any cultivable land, in fields, home gardens, canal borders, etc. in every Vietnamese
village. Usually poor soils are reserved for sweetpotato cultivation. In intensive farming
systems, farmers usually practise intercropping of sweetpotatoes with beans, sesame,
corn or vegetables. The intercropping system not only increases the total production
in a unit area, but also greatly contributes to soil improvement, and pest and disease
control of the secondary crops. After the main production season of sweetpotato, its
clonal maintenance in home gardens is the means of keeping “clonal seed” for the next
growing season.
Sweetpotato has diverse uses. This is an important food source for both people and
animals. As human food, storage roots and young leaves are used. Sweetpotatoes are
consumed fresh or dried for storage over several months. As animal feed, all parts of
the sweetpotato plant are used. The importance of sweetpotato as food and feed has
declined since the early 1990s. This has several reasons: Rice production in Vietnam
now exceeds the country’s self-sufficiency needs. Owing to the rise in the standard
of living, the Vietnamese people replace sweetpotatoes in their diet increasingly with
rice. The present economic development in Vietnam has led to the intensification
agriculture. Moreover, sweetpotatoes are being replaced by high protein feed
concentrates in the husbandry of pigs and other animals. The current situation of
sweetpotato production in the country calls for a new action plan to prevent genetic
erosion and for re-orientating the approach for its genetic conservation.
Activities of conservation of sweetpotato germplasm in Vietnam
Although sweetpotato did not originate in Vietnam, the crop is diverse in this country.
This is because of the following reasons:
– Sweetpotato has been cultivated in Vietnam for a long time.
– Sweetpotato ranks as the third staple food crop in Vietnam and is cultivated widely
all over the country.
59
The territory of Vietnam stretches over 15 degrees (from 8°30’N to 23°30’N) and displays
a range of diverse agro-climatic conditions, from the seasonal warm-temperate
conditions in the north to the wet tropical conditions in the south.
Collecting and conservation of sweetpotato germplasm in Vietnam were initiated
with great efforts in the1950s, years after the First Indochina Patriotic War. Almost all
germplasm were lost during the Second Patriotic War (1964–1975). After reunification
of the country, genetic conservation of sweetpotato started again along with the
promotion of conservation and use of plant genetic resources for food and agriculture.
The following are the main features of sweetpotato germplasm conservation in Vietnam.
Collecting of germplasm
The collection of Vietnamese sweetpotato germplasm is preserved in the field genebank
at the National Crop Genebank under the management of PGRC. Before 1996, the
sweetpotato collection was maintained in experimental plots in the field. In 1994, due
to a calamity of inundation, more than one hundred accessions were lost. Since 1995,
the collection has been kept in ceramic pots.
Number of conserved accessions:
–
–
–
–
–
Number of accessions collected before 1990
Number of accessions collected and introduced during 1990–96
Number of accessions collected after 1996
Total number of accessions collected
Number of accessions actually preserved
114
519
14
647
524
Composition of collection according to origin:
–
–
–
Number of local accessions
Number of introduced accessions
Number of improved and released varieties
402 (77%)
86 (16%)
36 (7%)
Number of accessions cultivated in production and used in breeding
programme:
–
–
50 varieties (10% of the total) are widely cultivated.
20 varieties (4% of the total) are frequently used as parents in breeding programmes.
It is estimated that the actual preserved collection represents only half of the total
genetic diversity of sweetpotato in Vietnam. There are specific remote areas that have
not yet been covered by collecting missions. Further collecting activities need to be
conducted to fill geographical gaps.
Characterization and evaluation of germplasm
Much attention has been paid to the issue of characterization and evaluation of crop
germplasm as this is an important part of the strategy of plant genetic resources
conservation of the NPGR Programme. All the collected or introduced germplasm
accessions have their corresponding passport data. The following are figures on
characterization and evaluation:
– All the varieties have morphological characterization data.
– 420 varieties (81% of the total) have evaluation data on agronomic characters,
horizontal pest and disease resistance traits.
60 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Vietnam has no facility for molecular characterization of sweetpotato germplasm,
even though this is an important aspect of germplasm characterization and evaluation.
PGRC plans to strengthen the Laboratory of Plant Genetic Diversity in the use of new
biological techniques to analyze and study the genetic diversity of crop germplasm.
It is hoped that, in the near future, a number of specific varieties of sweetpotato
germplasm can be characterized adequately by molecular techniques.
Characterization of flowering and botanical seed conservation
In Vietnam, sweetpotatoes are seen flowering between October and February, with the
majority of accessions flowering between November and December. The following are
data on flowering characterization of the collection:
– 246 varieties (50%) flower.
– 34 varieties (7%) produce botanical seeds.
Sweetpotato is an hexaploid species. Due to self-incompatibility, it does not set
botanical seeds if it is grown in isolation. When different varieties that flower are grown
together, cross-pollination occurs and heterozygotic botanical seeds are produced. When
such seeds are grown, they segregate for many generations, and the true genotype of
the original maternal variety cannot be re-constituted. Our objective is to conserve
genotypes, hence we have no interest in maintaining segregated botanical seeds in the
genebank. The botanical seed of sweetpotato produced by inducing flowering and then
by natural or artificial crossing can be considered as an acceptable way of long-term
genetic conservation of genes, if it is more important than conserving genotypes.
However, the possibility of using valuable genes obscured in heterozygotes is still far
removed from the realities of breeding programmes in developing countries.
Identification of duplicate accessions
Sweetpotato being a vegetatively propagated crop has practically no genetic
contamination even if a variety is cultivated for a long time in a particular area. However,
as a consequence of a variety being grown for a long time simultaneously in several
places, duplicate samples might have been collected. After agromorphological
characterization, the following 18 characters are used to identify duplicates of a
sweetpotato variety:
– Climbing ability
– Shoot tip pubescence
– Plant type
– Colour of leaf veins
– Stem diameter
– Pedicel length
– Stem pigmentation
– Pedicel colour
– Internode length
– Root shape
– Leaf shape
– Colour of root skin
– Leaf size
– Thickness of root skin
– Mature leaf colour
– Colour of root flesh
– Immature leaf colour
– Form of root-stem connection.
Results show that 223 accessions or 43% of the total are duplicates. The maintenance
of duplicate accessions is not necessary. However, agromorphological characterization
is not enough to confirm putative duplicate accessions as genetically identical. Molecular
techniques are considered as the most advanced methods to ascertain the duplicate
status of an accession. Duplicate accessions need to be conserved until their positive
identification.
61
Field genebank management
The Vietnamese collection of sweetpotatoes is conserved at the National Crop Genebank.
The field genebank was established in 1992 at the Tuber Crop Research Centre. In 1995
it was transferred to PGRC, which is responsible to manage the National Crop Genebank.
There are two forms of keeping the varieties in the field genebank:
– For germplasm maintenance sweetpotato accessions are cultivated in ceramic pots,
35 cm in diameter and 35 cm in height. Two pots are kept per accession. After six
months, plants are transferred to pots with new substrate.
– For characterization and evaluation, germplasm is cultivated in experimental plots
in the field. The size of the plots is 1 m x 5 m.
In vitro conservation
In vitro conservation was experimented at the National Crop Genebank in 1993–94. Two
problems were found:
– It was too expensive for conditions of Vietnam in comparison with conservation
in the field genebank. This higher cost is due to the fact that, unlike in developed
countries, in a developing country like Vietnam, chemicals and laboratory facilities
are expensive while labour is cheap.
From the late 1980s to the early 1990s, much progress has been made in developing
and using in vitro techniques, especially at the international agriculture research centres,
as a predominant approach for the conservation of vegetatively propagated crops. After
that, the actual use of tissue culture in plant genetic conservation has declined. It plays
nowadays a limited role even in developed countries. The main problem in developing
tissue culture technique as a promising method of plant genetic conservation appears
to be the difficulty of dealing with mutations. The actual strategy of plant genetic
conservation of Vietnam considers a role for in vitro conservation in the conservation
of difficult material, that is accessions that are seed-sterile or difficult to maintain in
the field.
Plans for the future
As was noted in the introductory section of this paper, excess of rice production and
agricultural intensification have reduced the scope of sweetpotato production for both
human use and animal feed. The production area of sweetpotato has therefore decreased.
In order to adapt to the new production trend, it has been found necessary to reorient
the approach for conservation of sweetpotato genetic resources in Vietnam. The following
are the main activities to be done:
• Collecting germplasm in areas previously not covered by collecting missions, thus
filling ecological gaps in collections
• Identifying duplicates and studying the issue of their maintenance
• Studying and implementing in vitro conservation for accessions that are difficult
to be preserved in the field genebank
• Improving the field genebank preservation
• Promoting the use of sweetpotato germplasm collection through detailed evaluation,
documentation and propaganda
• Promoting linkage of genetic conservation with research development through
diversifying the use of sweetpotato products
• Studying and implementing on-farm conservation and conservation through
widening use of germplasm.
62 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Fig. 1 Sweetpotato germplasm in pots at PGRC, VASI in Year 2001
Fig. 2 Sweetpotato germplasm in the field at PGRC, VASI in Year 2001
63
Recent Progress in the Conservation and Use of Sweetpotato
Germplasm in India
S.K. Naskar1, C.S. Easwari Amma2 and S.G. Nair2
Centre of CTCRI, Bhubaneswar-751 019, India; 2Central Tuber Crops Research
institute, Trivandrum, India
1 Regional
Introduction
Sweetpotato has its origin in northwestern South America and it was introduced to
India by the Portuguese during the 16th century. Now, it is an important rootcrop and
is grown in almost all parts of the country. In 1997, sweetpotato was grown on an area
of 141 000 ha and had an annual production of 1.174 million tonnes with productivity
of 8.326 t/ha (Table 1). The major area of production lies in the east and northeastern
parts of the country. The consumption of sweetpotato is high among the rural poor.
Farmers in rural areas grow several varieties or mixtures of varieties, which are the
building blocks of sweetpotato improvement programme in India.
Table 1. Area production and productivity in India
Source: FAO production year book Vol. 51–1997.
Year
Area
Production
Yield
1000 ha
1000 mt
kg/ha
1989–91
156
1265
8109
1995
138
1128
8174
1996
141
1174
8326
1997
141
1174
8326
Germplasm collecting
Germplasm collecting work has been going on in India since 1963 (Naskar et al. 1996).
The Central Tuber Crops Research Institute (CTCRI), Trivandrum, its Regional Centre
in Bhubaneswar and the 12 centres under the All India Coordinated Research Project
(AICRP) on Tuber Crops Other Than Potato have the responsibility of collecting
sweetpotato germplasm from different parts of India. But CTCRI has the mandate for
germplasm collecting and its conservation. Additionally, the National Bureau of Plant
Genetic Resources (NBPGR), New Delhi, and its Regional Station in Amravati are also
collecting and conserving sweetpotato germplasm.
Current status
In India, different institutions maintain a total of 3073 accessions of sweetpotato (Table
2). Since the last ANSWER meeting in 1996, 810 accessions have been added to
sweetpotato collection. Of these, 798 accessions are maintained by CTCRI. Among the
co-ordinating centres, Rajendra Agricultural University (RAU), Bihar and Tamil Nadu,
are other centres conserving maximum numbers of collections.
Tables 3 and 4 provide details of the composition of CTCRI’s collection. As seen
in these tables, landraces and native cultivars predominate in that collection, followed
by introduced materials and breeding lines.
64 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Table 2. Number of sweetpotato germplasm accessions maintained by different organizations/
centres in India
No. of Accessions
Organisation/ Centres
Place and State
1998
1996
CTCRI
Trivandrum, Kerala
847
807
RC of CTCRI
Bhubaneswar, Orissa
239
253
RAU
Dholi, Bihar
802
709
APAU
Rajendra Nagar, Andhra Pradesh
95
85
BCKV
Kalyani, West Bengal
100
70
AAU
Jorhat, Assam
29
25
KKVP
Dapoli, Maharashtra
118
118
NEH complex
Shillong, Meghalaya
31
31
BAU
Ranchi, Bihar
94
89
NDAU
Faizabad, Uttar Pradesh
63
3
GAU
Navasari, Gujarat
30
NA
IGKV
Jagadalpur, Madhya Pradesh
85
73
TNAU
Coimbatore, Tamil Nadu
540
NA
NBPGR
Amravati, Maharashtra
NA
NA
Table 3. Number of accessions of cultivated and wild Ipomoea
accessions maintained in CTCRI and its Regional Centre
Type of Germplasm
No. of Accessions
CTCRI
Indigenous
547
Exotic
322
Ipomoea species I. aquatica, I. trifida,
5
I. triloba, I. setosa, I. batatas var. batata)
Regional Centre
Landraces
25
Breeding materials
146
CTCRI accessions
56
Ipomoea species
I. trifida germplasm
80
I. triloba
2
I. aquatica
1
I. nil
1
Table 4. Percentage of holdings of native cultivars, breeding
lines and released varieties of CTCRI sweetpotato germplasm
collection
Type of Holding
Percentage
Native cultivars
43
Breeding lines
19
Introductions
37
Released varieties
1
65
Characterisation and documentation
In CTCRI, about 800 accessions have been characterised morphologically (Table 6) and
764 accessions have been documented in a computerised database (Rajendran et al. 1992).
Passport data are available for 825 accessions. Farmers’ knowledge or indigenous
knowledge is known for 371 accessions. Molecular fingerprinting has not been tried.
Agronomic evaluation data are available for 200 accessions.
In sweetpotato, about 100 species of pests are known attacking it. Among them the
sweetpotato weevil (Cylas formicarius Fab.) is a major pest causing extensive damage
and reduction in yield. About 750 accessions in CTCRI and 163 accessions in its Regional
Centre have been screened for weevil infestation. All the accessions screened so far
are susceptible to weevil at different levels. At CTCRI, 10% of total accessions screened
are less susceptible to weevil infestation with storage root damage ranging from 2 to
21.0%.
A total of 985 accessions in CTCRI and its Regional Centre were screened for their
reaction to different diseases under field condition. Out of 822 accessions screened at
CTCRI, 29 were observed to be free of all diseases and the rest were affected by one
or more diseases. Among the virus diseases, chlorotic leaf spot was observed in 498
accessions, ring spot in 354 accessions and leaf roll in 73 accessions. Besides, other
symptoms presumably produced by virus like diseases such as puckering was observed
in 305 accessions, fan leaf in 49 accessions, internal chlorosis in 26 accessions and yellow
netting in 4 accessions (Table 7). Among the fungal diseases, chlorotic leaf distortion
(CLD) was observed in 400 accessions and brown leaf spot in 207 accessions (Table
7). As biochemical analyses like starch, sugar, carotene, etc. are not completed for the
accessions, update of catalogue has not been done.
Conservation activities
In India, sweetpotato germplasm is maintained in field genebanks (FGB). The germplasm
accessions are replanted thrice in a year (Naskar et al. 1997). Where rainfall is well
distributed throughout the year, sweetpotato is reproduced from vines taken from the
previous crop. Occasionally, sweetpotato is conserved in the form of storage roots kept
spread out in the shade, for example, in the Indo-Gangetic Plain.
In vitro conservation is the safest way to conserve germplasm. At present 100 and
14 accessions are transferred in vitro in CTCRI and its Regional Centre respectively.
Initial establishment of germplasm was done through meristem culture in Murashige
and Skoog (MS) media with 0.1 uM, NAA, 0.1 uM BA and 0.01 uM GA3. The accessions
are then multiplied in MS medium without plant growth regulators. Cultivars are
inoculated and incubated at 25–28°C under 8 hours of light (3000 lux). For slow growth
mannitol (3%) and sucrose (2%) are effective.
Germplasm utilisation
In India, so far 19 varieties have been released by different organisations. Nine varieties
were released by CTCRI and 10 varieties by different AICRPTC centres (Table 5). The
main breeding objectives in India are development of high yielding varieties with
improved quality along with early maturity and resistance to different biotic and abiotic
stresses. The regional centre of CTCRI in Bhubaneswar has also developed salt tolerant
and drought tolerant lines and the former are being tested in salt affected areas. Efforts
have also been made to develop high starch varieties and a few lines have been identified
for further testing.
66 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Table 5. Recommended sweetpotato cultivars in India
Cultivar
Yield (t/ha)
Skin Colour
H-41
20–30
Pink
H-42
20–25
Pink
VL-Sakarkand
20
Purple
Co-1
20–30
Light pink
Co-2
25–30
Light pink
Co-3
25–30
Light red
Rajendra Sakarkand-5
24–30
White
H 268(Varsha)
20–25
Pink
Sree Nandini
20–25
White
Sree Vardhini
20–25
Pink
Samrat
20–28
Dark brown
Rajendra Sakarkand 43
20–25
Brown
Rajendra Sakarkand 35
20–30
Brown
Kiran
22–30
Brown
Rajendra Sakarkand 47
25–32
Red
Sree Rethna
20–26
Purple
Sree Bhadra
20–27
Pink
Gouri
20–25
Purple
Sankar
14–20
Red
Flesh Colour
White
White
Light yellow
White
White
Orange
White
Light yellow
White
Orange
White
White
White
Orange
White
Orange
Cream
Deep orange
White
Year of Release
1971
1971
1974
1976
1980
1980
1985
1987
1987
1987
1987
1994
1994
1994
1997
1997
1987
1998
1998
Table 6. Descriptive information available on the CTCRI germplasm
Information Available
No. of Accessions
Botanical seeds
500
Passport data
825
Farmers IK
371
Morphological characterisation
800
Molecular finger print
None
Evaluation data agronomy
200
Pests (Weevils)
700
Diseases
822
Table 7. Germplasm accessions affected by different pests and diseases
Pests and Diseases
No. of Accessions
Pests
Weevil
913
Diseases
983
No. of disease
29
Viruses
Chlorotic leaf spot
498
Ring spot
354
Leaf roll
73
Virus like diseases
Puckering
305
Fan leaf
49
Interveinal chlorosis
26
Yellow netting
4
Fungal diseases
Chlorotic leaf distortion (CLD)
400
Brown leaf spot
207
67
Outlook
India is maintaining more than 3000 accessions of sweetpotato, many of which are
duplicates. Therefore, identification of duplicates must be a priority of the future
germplasm conservation strategy. Though efforts in this regard have been initiated in
CTCRI, such work has not been started in other centres. A core collection comprising
105 accessions has been identified in CTCRI. Similar work will be taken up in other
centres during the coming years. The duplicate identification would be based on
preliminary grouping using biochemical and morphological descriptors with high
reliability. The core collection, duplicate identification in other centres and in vitro
conservation and cryopreservation are the future strategies for sweetpotato germplasm
conservation. Complementary conservation strategies will include in situ conservation
and seed storage.
References
Naskar, S.K, C.S. Easwari Amma and S.G. Nair. 1996. Sweetpotato genetic resources
in India. Pp. 57–80 in Proceedings of a Workshop on the Formation of a Network
for the Conservation of Sweetpotato Biodiversity in Asia (V. Ramanatha Rao, ed.).
Bogor, Indonesia, 1–5 May, 1996. IPGRI APO, Singapore.
Rajendran, P.G., C.S. Easwari Amma and K.R. Lakshmi.1997. Description, documentation
and evaluation of sweetpotato germplasm. Central Tuber Crops Research Institute,
Sreekariyam, Thiruvananthapuram-695 017.
68 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Appendix 1. Programme
Workshop on
Asian Network for Sweetpotato Genetic Resources (ANSWER):
Strengthening National Capacity and Regional Collaboration
Bogor, Indonesia: November 2–5, 1999
November 2, 1999
Arrival of participants
November 3, 1999
08.00–08.30
Registration
Opening and Overview
08.30–08.40
Opening: Dr M. Jusuf, (Chairman, ANSWER)
08.40–08.50
Welcome: Dr Gordon Prain, (CIP-ESEAP)
08.50–09.00
Welcome: Dr V. Ramanatha Rao (IPGRI)
09.00–09.30
Overview: Background, major issues and goals of the workshop
– Dr Michael Hermann, (CIP-HQ)
Country Reports
(Presentation: 15 minutes; Discussion: 15 minutes)
09.30–10.00
Sri Lanka: Mrs P.S.A.D. Prematilake
10.00–10.15
Coffee break
10.15–10.45
Malaysia: Dr Mohd Said Saad
30.30–30.30
Indonesia – National collections- Indonesia and Irian Jaya: Dr M.
Jusuf/Mr Ery Atmojo
11.30–12.00
CIP’s Asian Sweetpotato Collection: Mr Tjintokohadi
12.00–13.00
Lunch
13.00–13.30
Philippines: Prof Algerico Mariscal
13.30–14.00
Thailand: Mr Narin Poolperm
14.00–14.30
Vietnam: Dr Luu Ngoc Trinh
14.30–15.00
India: Dr S.K. Naskar
15.00–15.15
Coffee break
15.15–15.45
China:Dr Guo Xiaoding
15.45–17.00
Discussion and Synthesis
19.30
Opening dinner
69
November 4, 1999
Project Planning Workshop
08.00–08.30
Workshop procedures
08.30–10.00
Analysis of persisting problems: Plenary workshop
10.00–12.00
Research response to problems: Working group 1/Working group 2
12.00–13.00
Lunch
13.00–15.00
Research response to problems (continued): Working group 1/
Working group 2
15.00–15.15
Coffee break
15.15–17.30
Presentation and discussion by working groups
November 5, 1999
Project Planning Workshop (continued)
08.00–10.00
Network organization: Plenary workshop Prioritizing minimalfunded and fully funded research
Working group 1
Working group 2
13.00–13.30
Lunch
13.30–15.30
Presentation of working groups on prioritized research
15.30–15.45
Election of coordinator
15.45–16.00
Closing ceremony
70 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Appendix 2. List of Participants
Dr Guo Xiaoding
Assistant Director
Xuzhou Institute of Agricultural Science
Xuzhou Sweetpotato Research Centre
Donghecun East Suburbs
Xuzhou
Jiangsu 221121
P.R. China
Tel : 86-516-3352146
Fax: 86-516-3350318
E-mail: [email protected]
Dr S.K. Naskar
Head, Regional Centre of the Central
Tuber Crops Research Institute (CTCRI)
Dumduma Housing Board
PO Bhubaneswar
India 751019
Tel : 91-674-470528
Fax: 91-674-470528
E-mail: [email protected]
Dr M. Jusuf
Plant Breeder, Research Institute for
Legume and Tuber Crops (RILET)
Jl. Raya Kendal Payak
PO Box 66
Malang
Indonesia
Tel : 62-0341-801468
Fax: 62-0341-801496
62-0341-801075
E-mail: [email protected]
Mrs St. A. Rahayuningsih
Plant Breeder, Research Institute for
Legume and Tuber Crops (RILET)
Jl. Raya Kendal Payak
PO Box 66
Malang
Indonesia
Tel : 62-0341-801468
Fax: 62-0341-801496
62-0341-801075
E-mail: [email protected]
Mr Ery Atmojo
The Root and Tuber Crops Research
Centre
Cendrawasih University
Jl. Gunung Salju
Manokwari
Irian Jaya
Indonesia
Tel : 62-0968-214971
Fax: 62-0968-211455
Mrs Minantyorini
Researcher, Research Institute for Food
Crop and Biotechnology (RIFCB)
Jl. Tentara Pelajar
Bogor
Indonesia
Tel : 62-0251-338820
Fax: 62-0251-338820
E-mail: [email protected]
Dr Luu Ngoc Trinh
Director, Genetic Resources Centre
VASI
Vietnam
Fax: 861-3937
E-mail: [email protected]
Prof Algerico Mariscal
Associate Professor / Plant Breeder
Philippine Rootcrop Research and
Training Centre (PRCRTC)
VISCA
Baybay
Leyte
Philippines 6521-A
Tel : 63-53-335-2616
Fax: 63-53-335-2616
E-mail: [email protected]
Mr Narin Poolperm
Plant Breeder
Department of Agriculture
Phichit Horticultural Research Centre
Phichit 66000
Thailand
Tel : 66-56-612352
Fax: 66-56-612351
71
Mrs P.S.A.D. Prematilake
Research Officer
Horticultural Research and Development
Institute (HORDI)
PO Box 11
Gannoruwa
Peradeniya
Sri Lanka
Tel : 94-8-388234
Fax: 94-8-388234
E-mail: [email protected]
Dr Mohd Said Saad
Programme Head
Plant Genetic Resources Centre
Institute of Bioscience
Universiti Putra Malaysia
43400 Serdang
Malaysia
Telephone: 6-03-9486101 ext 4077; Fax: 603-9423087
E-mail: [email protected]
Dr V. Ramanatha Rao
Regional Director (Interim) and Senior
Scientist (Genetic Diversity/Conservation)
International Plant Genetic Resources
Institute (IPGRI)
Regional Office for Asia
the Pacific and Oceania (APO)
P.O. Box 236
UPM Post Office
43400 Serdang
Selangor Darul Ehsan
Malaysia
Tel : 603- 9423891
Fax: 603- 9487655
E-mail: [email protected]
Dr Michael Hermann
Project Leader:
Conservation & Characterization of
Sweetpotato Genetic Resources
International Potato Centre (CIP)
Avenida La Universidad 795
Apartado Postal 1558
Lima 12
Peru
Tel : 51-1-3496017
Fax: 51-1-3495638
E-mail: [email protected]
Dr Gordon Prain
Regional Director
International Potato Centre (CIP)
Regional Office for East, Southeast Asia
and the Pacific (ESEAP)
Kebun Percobaan Muara
Jl. Raya Ciapus, Bogor 16610
Indonesia
Tel : 62-251-317951
62-251-313687
Fax: 62-251-316264
E-mail: [email protected]
Mr Tjintokohadi
Research Assistant
International Potato Centre (CIP)
Regional Office for East, Southeast Asia
and the Pacific (ESEAP)
Kebun Percobaan Muara
Jl. Raya Ciapus, Bogor 16610
Indonesia
Tel : 62-251-317951
62-251-333667
Fax: 62-251-316264
E-mail: [email protected]
Ms Caecilia A. Widyastuti
Research Assistant
International Potato Centre (CIP)
Regional Office for East, Southeast Asia
and the Pacific (ESEAP)
Kebun Percobaan Muara
Jl. Raya Ciapus, Bogor 16610
Indonesia
Tel : 62-251-317951
62-251-333667
Fax: 62-251-316264
E-mail: [email protected]
Mr Sukendra Mahalaya
Information Management Officer
International Potato Centre (CIP)
Regional Office for East
Southeast Asia and the Pacific (ESEAP)
Kebun Percobaan Muara
Jl. Raya Ciapus, Bogor 16610
Indonesia
Tel : 62-251-317951
62-251-333667
Fax: 62-251-316264
E-mail: [email protected]
72 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
Appendix 3. Summary Tables from Group Discussions
GROUP 1
RESULTS OF DISCUSSION
No.
1
Issue
Germplasm
collection
Problem
Geographical gaps
in collection
Output
Geographical gaps
filled
Action
Determine previously
unexplored areas
Map areas where
farmers’ varieties are
under threat
Collect in priority areas
as well as priority
materials (responsible
by country
2
3
Core
collection
Germplasm
utilization
Erosion of farmers’
varieties is not known
No strategy for
collecting
Lack of fund to perform
the collecting areas
Lack of guidelines on
core sample or core
collection
Collecting strategy
developed
Guidelines
developed
How to establish a
core collection
Core collection
established
Inadequate germplasm
utilization
Utilization of
germplasm (core
collection)
increased
Compile guidelines from
the other crops
Determine core
collection method
Complete
characterization and
documentation
Identify accessions
based on
characterization data +
geographical + IK
information, etc.
Evaluate germplasm
concerning agronomic,
pest and disease,
quality
Develop molecular
markers for efficient
selection of quality traits
Provide information on
germplasm
Introduce desired
accessions
73
No.
4
Issue
Conservation
strategy
Problem
High cost of in vitro
culture
Output
Cost reduction
strategy developed
Action
Identify priority
accessions, then
conserve them in in
vitro culture
Improve efficiency by
developing protocol
Rationalize the
collection maintained
Standardized
cryopreservation
protocol developed
Seed conservation
methodology
developed
Field genebank
management
system developed
Undertake research
activities to develop
protocol
Induce flowering and
seed setting
High cost of large field
collection
Lack of optimum
cryopreservation
Uncertainty about
method for seed
conservation
Need to perfect the field
genebank conservation
Hard to find in situ
conservation place
Difficulties and safe
guarding of cultivars in in
situ conservation
Methodology to
identify site for insitu conservation
developed
Cultivars in situ
safe guarded
Develop filed genebank
management system
Develop farmer
participatory research
Monitor the movement
of cultivars by farmers
every season (new
gardens)
74 CONSERVATION AND UTILIZATION OF SWEETPOTATO GENETIC DIVERSITY IN ASIA
GROUP 2
MANAGEMENT PROBLEMS
Output
Pest and disease free materials
Activity
Clean all virus infected materials G
Guidelines for pest and disease handling &
management
Fully equipped genebank in
environmentally friendly environment
FGB in less problematic area
Share activities that require high cost
Information on germplasm behavior
Study relation of environment & character change
List/guide for characters behavior
Trained personnel for genebank
management
BSc as minimum qualification
Standard training through ANSWER
DATABASE MANAGEMENT
Output
Standard descriptors for duplicate
identification & management/utilization
Activity
Adopt Huaman + yield, dm, and/or molecular to
further Co confirm duplicates
Standard database system
Use excel (standard form to be developed)
Every member to use the same format and transfer
data int to the new system
Centralized database system
CIP as the clearing house/manager
PROBLEMATIC ACCESSIONS
Output
Use artificial seed technology
Activity
Protocol for artificial seed production
Proper field technique
Us Use flowering induction methods
Planting for more than 3 seasons