1. Featuring the Oregon Wolfe Barley
Linkage mapping of single genes determining notable phenotypes of economic value
Featuring the Oregon Wolfe Barley
nud kap lks2

2. A quick review of doubled haploids
Gametes (male or female)
Nud nud (n = 7)
F1 = Nud nud (2n = 2x = 14)
Induction/regeneration
Nud
nud
Mature plants/grain
Haploid plantlets (n = 7)
Nud Nud
nud nud
(2n = 2x = 14)
Chromosome doubling (spontaneous/induced)

3. Hordeum bulbosum DH production in barley
Emasculate H. vulgare
H. bulbosum pollen
The Hordeum bulbosum method to produce doubled haploid barley.
P. Devaux: Florimond Desprez, Biotechnology Laboratory, P.O. Box 41, Cappelle en Pevel,e, France.
Pollinate H. vulgare with H. bulbosum
Leave ~ 10 days for embryo to develop

4. Hordeum bulbosum DH production
Tissue culture developing embryos
Colchicine
Produce seed
Breeding/genetics forever
The Hordeum bulbosum method to produce doubled haploid barley.
P. Devaux: Florimond Desprez, Biotechnology Laboratory, P.O. Box 41, Cappelle en Pevel,e, France.

5. Anther Culture DH production in barley
Harvest donor spikes
Apply stress conditions
Place anthers on induction medium
Sub-culturing for shoots and roots
Spontaneous doubling
Produce seed
Breeding/genetics forever

6. OWB dominant x OWB recessiveF1
Doubled haploids

7. Heart disease, high cholesterol, obesity
Eating barley can help address these challenges
- soluble dietary fiber
But who wants to eat hulls?
- insoluble dietary fiber
Options for no hulls
Pearling
Naked barley

8. Score the phenotype with samples provided and add to the linkage map
Hulled and naked (hulless)
Let’s map the gene!
Score the phenotype with samples provided and add to the linkage map
Taketa, S. et al PNAS 105:

9. Hooded varieties are better for forage than awned varieties
Awns are painful to livestock (and humans)

10. Hooded and awned Let’s map the gene!
Score the phenotype with samples provided (or online images) and add to the linkage map
Muller et al. Nature. 1995: 374:
McCoy, S.B OSU scholars archive

11. Nud maps fine (expected segregation and map location)
But what is going on with Kap?
Not expected segregation
Not expected map location
Don’t look at the next slides until you’ve been through the two readings on Kap
Develop your own strategies to map Kap, based on the readings.
Now go to the next slides.

12. A summary of the epistatic interaction
The Kap locus: Kap_ confers the hooded phenotype; kapkap = short-awned.
The LKs2 locus: Lks2_ confers long awn phenotype; lks2lks2 the short awn phenotype
BUT Kap and LKs2 interact: the long awn phenotype is not visible when the dominant allele is present at the Kap locus.
KKLL = hooded (no awns)
KKll = short awns (no hoods)
kkLL = long-awned (no hoods)
kkll = short awns (no hoods)

13. Moving ahead with mapping
Based on the epistatic model, Lks2 can be mapped (although there are complications deciding how long is long and how short is short) because you can impute that all hooded types are LL, that all long-awned types are kkLL and that all short-awned types are ll.
Kap, however, is still problematic.
KKll and kkll genotypes cannot be distinguished based on phenotype.
What about based on genotype?
hvnox3 is in the map data set: based on the allele scores provided, each of the OWB lines can be assigned a Kap or a kap allele type.
Now you can assign genotypes to each OWB DH at the two loci.