Pre-breeding in annual legumes
MLA project B.PBE.0037
Phil Nichols
Department of Agriculture and Food Western Australia
The project team
What we did
Developed new tools & technologies to increase
rate of genetic gain in annual legume breeding
• To reduce cultivar development time
• To determine genetic diversity for important traits
─Is their sufficient variation for plant breeding?
─Can we identify the genes involved?
• To develop molecular markers for important traits
Sub clover core collection origins
─For more efficient breeding and selection
Species
• Determined at an industry workshop in 2013
• A high emphasis on subterranean clover
─Utilised the ‘core collection’ of 97 highly diverse lines
and 28 cultivars
• Some work on annual medics and other legumes
Outputs and beneficiaries
• Genetic information and molecular markers for public
and private breeding programs – immediate users
• Graziers will benefit from more productive and
persistent cultivars with genes for new traits
Sub clover core collection & cvs.
Developed a sub clover genomic platform
Published the sub clover genome sequence
• cv. Daliak is the reference genome
• Allows identification of the genetic basis of agronomically
important traits in sub clover
Characterised 125 core collection lines and
cultivars at the DNA level
• Developed high density SNP maps
Can now associate genetic differences for traits
with differences in DNA markers
• Comparison of DNA sequences to the reference genome
Outcome will be DNA markers for traits of interest
• Enables simultaneous genomic selection for many genes
• Especially important for traits difficult to measure
Can also relate trait and DNA information to site
collection data
• Understanding of traits and genes important for
adaptation to different environments
Key message: This technology allows more efficient and precise selection
of sub clovers containing genes for new traits - leading to more
productive and persistent sub clovers
Phenotyped sub clover core collection & cvs
Measured 30 agro-morphological traits
• Flowering time, leaf marks & other morphological
characters, plant and seed characters
Seedling growth parameters
RLEM seedling resistance
Oestrogenic isoflavones
Spaced plant trial
• Formononetin, genistein & biochanin A
Hardseededness and timing of seed softening
Integration of phenotyping from other projects
• Phosphorous-use efficiency and root growth traits (MLA)
• Methanogenic potential (ARC)
• Resistance to important diseases (RIRDC)
Seedling growth traits
Wide diversity found for each trait
Candidate genes being identified
Molecular markers will be designed for markerassisted breeding and genomic selection
Key message: New genes and new traits have been
found that can be exploited to breed more
productive and persistent sub clovers
RLEM screening
Annual medics and other legumes
Adapted a boron tolerance molecular marker in
barrel medic for use in burr & stand medics
• This will lead to more efficient breeding of annual
medics for B tolerance
Diversity found for seedling growth, independent
Boron susceptibility
of seed size, in barrel and strand medics
Diversity found for seedling resistance to RLEM
among 156 annual medics in 14 species
Key message: New genes and new traits have
been found that can be exploited for breeding
more productive and persistent medics
Hardseededness and timing of seed softening in RLEM screening
38 annual legumes are being examined in Perth,
Adelaide and Canberra
• This will provide a better understanding of diversity
within species and the effects of environment on hard
seed traits
Hard seed trial - Perth
Increased generation turnover rates
Developed a rapid generation protocol for sub clover
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Grow 3-5 generations per year (1 per year currently)
Reduce time to flower - vernalise and subject to 18 hours photoperiod
Harvest immature burrs from first flowers and culture embryos on agar
Transplant to pots and repeat
Extended protocol to annual medics and serradellas
Key message: Improved cultivars can reach the paddock at least 3 years
sooner
Unanswered questions
How do we best incorporate these technologies into practical breeding
programs?
How reliable and cost-effective will the genetic markers be?
• They will need to be validated in the field
How do we most efficiently combine genes for a range of important
traits into single genotypes?
• MAGIC (Multiparent advanced generation intercross) populations used in some
cereal programs could be tested in sub clovers and medics
What exploitable diversity is there for other important traits?
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Nutritive value (green and sensesced)
N fixation
Harvestability – traits for easier seed harvest
Others
Can we extend these technologies to other important pasture legumes?
• Other annual clovers
• Serradellas & biserrula
• Perennial legumes – lucerne, white & red clovers
What is the economic value of individual traits (and genes) at the
paddock level?
Profit chart (for 2025+)
New annual legumes
bred with new tools
and technologies:
10% more total dm
x 50 mill ha
x 10% adoption
= 5 mill ha
20% more
autumn-winter
kg/ha dm/year
10% more
total kg/ha
dm/year
New annual legumes
bred with new tools
and technologies:
10% less P use
x 50 mill ha
x 10% adoption
= 5 mill ha
10% lower P
costs/year
New annual legumes
bred with new tools
and technologies:
10% less methane
emission
x 50 mill ha
x 10% adoption
= 5 mill ha
10% less
methane
emission/year
$15/ha
liveweight
gain/year
Additional
$75 mill
on-farm
value by
2025+