Transcript Breeding and Genetics Tools

Breeding and Genetics Tools
Dr. Brent Hulke
Research Geneticist
Tools available/under development
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Germplasm Resources
SNPs/genomic resources
Doubled Haploid
Evolution of the term “conventional
breeding”
Germplasm Resources
• Wild species
– Perennial species – “introgressions” by
C.C.Jan
– Annual species that are not H. annuus –
“introgressions” by Seiler and Qi
– Helianthus annuus itself and postintrogression taming – crosses by Hulke
Germplasm Resources
• Diverse breeding programs
– Multiple independent programs in Europe, South
America, USA
– Landraces of confection, in particular
– Open Pollinated Varieties available in Plant
Introduction Station collection in Ames
Frequency
Combined for Grandin '09 and Crookston '08 & '09 (adjusted)
50
45
40
35
30
25
20
15
10
5
0
46
46
32
27
27
22
8
10
9
4
2
5
2
0
0
0
15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65 65-70 70-75 75-80 80-85 85-90 90-95
Stalk Rot (%)
0
95100
Germplasm Resources
• The hybrid breeding system itself
– Advantages:
• faster improvement because you are improving
“female” and “male” lines simultaneously and with
respect to each other
• Take advantage of hybrid vigor that doesn’t exist in
pure line varieties (soybean, wheat, barley, beans)
– Disadvantages:
• “perfect” flowers make it difficult to make test
hybrids and requires development of male sterile
lines – extensive backcrossing – really expensive
Genomic Resources / SNPs
• SNP = single nucleotide polymorphism
– About 7500 quality SNPs available today
Arabidopsis thaliana EIN2 (Ethylene Insensitive 2) homologus gene sequences in cultivated Helianthus annuus lines
SNP
Genomic Resources / SNPs
• Traditional, 2 parent mapping – cross two
distantly related lines different for a trait of
interest, genotype and phenotype population,
run analysis – takes ~ 2 years
• Association mapping – No crosses made, use
phenotypes and genotypes from hundreds of
lines from diverse backgrounds – takes months
to years
• Genomic selection – No special crosses made,
just use existing breeding lines and phenotypes
– genotype with many markers and make model
Genomic Resources
• Single gene
– Disease resistance
• Many genes
– Disease resistance
• Downy mildew
• Sunflower rust
• Verticillium wilt
– Herbicide resistance
– High oleic
– Insect resistance???
• Phomopsis
• Sclerotinia stalk rot
• Sclerotinia head rot
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Insect resistance???
Yield
Oil content
Confection v. Oilseed
Single gene traits and Many gene (quantitative) traits
require different applications of SNP technology
Doubled Haploid
• 4 techniques
– Anther culture
– Microspore culture from anthers
– Foreign species pollen as inducer
– Mutant stock pollen/ovule as inducer
• None have been fully successful / proven
to date
Doubled Haploid
• Anther Culture
– Proper balance of chemical inducers,
generation of callus from haploid pollen
tissue, and regeneration of embryoids from
callus is under investigation
– We are able to get callus development at lowmoderate levels (best in interspecific hybrids)
– Root and shoot formation has not resulted
from this callus, which will require additional
experiments to overcome
Doubled Haploid
• Microspore culture
– Callus derived from individual pollen grains
instead of whole anthers
– Culture conditions currently still being
optimized
Doubled Haploid
• Foreign pollen
– Seeds of potential non-Helianthus annuus species
identified
• Criteria: high pollen production, ease of cultivation to harvest
the pollen
– A X B line crosses were made of confection and
oilseed backgrounds to make a sterile F1 hybrid
– Hybrids will be pollinated with foreign pollen in two
months, seeds collected in three months, and
seedlings germinated four months from now and
assessed for haploidy.
Doubled Haploid
• Development of H. annuus genetic stock with
haploid inducing ability
– Novel mutations will be induced in sunflower this
summer in our nursery
– Winter nurseries will be used to derive mutant lines
for testing
– Lines will be evaluated for spontaneous development
of haploid progenies
– Could produce both maternal and paternal haploids
(could be used for “instant CMS” and DH population
development) – similar to Stock 6 in corn
Doubled Haploid
• Goals:
– Reduce line development time from 5-7 years
to under 2 years
– Improve genetic purity of lines and hybrids
– Provide instantly “true breeding” material to
select optimum progreny using SNPs
– Make development of “female” inbreds a
single cross operation
“Conventional” Breeding
• With new technology, definitions will change, as
well as abilities
• Genomic prediction and marker based selection
based on markers will define what we actually
advance and put in yield trials
• Doubled haploid will allow us to test new hybrids
without years of inbreeding/backcrossing to CMS
• Additional germplasm resources from other
species may provide new genes to exploit without
transformation – not common in other crops