Genetic base broadening for cereals:
problems and goals
Vytautas Ruzgas
Lithuanian Institute of Agriculture
The main reason why we should think
about genetic base broadening
• The majority of top varieties have quite
narrow genetic pedigree. From the
biological point of view it is not desirable
• Resistance to pathogenes is a permanent
problem. Resistance genes are effective
not forever
• New goals require a new gene pool for
plant breeding.
Some examples:
• Common bunt is a limiting factor for organic farming. For
a long time it was not a problem due to seed treatment in
conventional agriculture
• For the development of varieties resistant to common
bunt the breeders need of appropriate parental material
• For new farming systems (ploughless etc.) farmers need
a new varieties resistant to Tan spot, Fusarium etc. The
range of varieties available for farmers and genetic
collections is rather small.
• Climate warming causes a new problems
• Roots: a new area for research acctivity
Thous. ha
Area under organic farming in
Lithuania
80
70
70,0
60
50
40
43,0
30
20
10
23,3
4,0
4,0
4,7
6,4
8,8
1998
1999
2000
2001
2002
0
2003
2004
2005
planas
Susceptibility to Common bunt in winter wheat
collection (more than 2000 varieties and lines were
investigated over the period 1993- 2006 )
80,0
68,4
70,0
60,0
%
50,0
40,0
30,0
20,0
20,0
10,0
10,0
0,1
0,5
0
0,1-5,0
1,0
0,0
5,1-10,0 10,1-30,0 30,1-50,0
Infecion %
50,1100,0
Genetic base broadening possibilities
using varieties of distant geographic origin
To obtain more diverse gene pool for breeding programmes
the Lithuanian Institute of Agriculture joined the International
Facultative and Winter Wheat Observation Nursery project,
initiated by CIMMYT.
The varieties for this project were collected from distant
origin , majority from South regions
Since 1993 more than 3000 varieties and lines have been
investigated
Some varieties were included in the crossing combinations
to get the initial material for further crosses
What was the adaptation of winter wheat
varieties from Southern countries
under Lithuanian conditions?
- High air humidity
- Chilly summers
- Changeable air temperatures in winter, sometimes
-25…..C0
Varieties from South regions:
susceptibility to winter conditions,
Lithuania, 1995- 2000
Varieties
(Investigated 940
varieties)
300
Širvinta
280
250
233
200
166
150
100
75
61
50
30
27
16
18
17
7
8
0
1
2
3
4
5
6
Suscepibility , scores
9
10
1 = 0-20 %
2 = 21-30 %
3 = 30-40 %
4 = 41-50 %
5 = 51-60 %
6 = 61-70 %
7 = 71-80 %
8 = 81-90 %
9 = 91-100 %
Varieties
Grain yield , 1995- 2000
(investigated
851)
250
207
150
125
121
100
81
85
Standard late variety)
168
Standard early variety)
200
50
36
25
3
0
1
2
3
4
5
6
Grain yield, t/ha
7
8
9
Protein content of winter wheat varieties
from South countries
(Varieties,%)
55
47,6
50
45
40,7
40
35
Širvinta
30
25
20
14
15
10
5
2,3
0
< 10.5 %
11.0-12.5 %
13.0-14.0 %
Grain protein content
> 14 %
Wheat from South regions: resistance to
diseases, 1995- 1998
Varieties
Standartd, late
250
150
210
Standard , early
200
192
179
162
Septoria tritici
126
101
100
87
87
64
50
Erysiphe graminis
67
58
45
8
10
1
6
0
1
2
3
4
5
1 - resistantat, 9 - very susceptible
6
7
8
9
• The majority of the winter wheat varieties from
arid climate countries exhibited sufficient winter
hardiness.
• The varieties from arid climate countries were
noted for early maturity. This trait is valuable in
the context of climate warming in the Baltic see
region.
• Resistance to Drechslera tritici-repentis is a
promising trait, but further studies are needed.
• The greatest constraints of the varieties from
arid climate countries to be included in breeding
programmes are low grain yield and
susceptibility to powdery mildew.
Starch quality
• Starch quality of winter wheat grain is a
recent problem.
• Starch producing industry requires
wheat grain characterised by:
- high starch quality: -higher share of
granules > 10 µm
- “waxy” wheat, whose starch consists of
amyl pectin and has no amylase
Starch granules: distribution of size
The size of granules is a limiting factor of starch quality , properties of
dough, output of alcohol and other properties
Section of “waxy” wheat grain
”Waxy wheat” starch has no reaction with iodine
“Waxy” wheat is desirable in dietary
bread- making
• For peoples who do not tolerate the gluten
Ordinary
wheat
Waxy
wheat
Blending of “waxy” and ordinary wheat
The main limiting factors in
breeding programmes
• Most starch type varieties have low
content of big- sized granules
• Most “waxy” wheat varieties are low
yielding and susceptible to diseases,
lodging problems etc.
• Great part of “waxy” wheat varieties are
not fully waxy in all 3 genomes
• Limited gene resources
Collection of waxy and exotic wheat
Farmers are interested only in high
yielding top varieties
The ultimate task for pre-breeding:
development of new attractive varieties with
improved genetic value
U
Thank you for attention
!