I wonder if you can help me with one matter. I am working with plants hybrids of f9 generation. Within one hybrid (e.g. Y x Z), I've got few individual accessions phenotypically diversified (Y x Z', Y x Z'' etc.). I wonder if these individuals can carry different genes (for example, leaf rust resistance genes)? If parental accession Y has leaf rust resistance gene Lr9 and the other does not, if its possible that hybrid 1 posses that gene and the hybrid 2 doesn't?
@ Adrian Duba ,
You have not mentioned the name of the crop.
Few individual accessions phenotypically diversified (few=???).
The accession Y (Lr resistant) & accession Z (not Lr resistance).
Say, when you cross YY x ZZ=in F1, all individuals will carry the gene (Lr resistant).
But on selfing F1 individuals, there will be a segregation into YY, YZ & ZZ.
At this stage, 25% individuals (ZZ) are without Lr resistant gene.
Like this, even in the next generations, both type of individuals will be there.
It is not clear from the question that whether selfing or back crossing is done.
Normally back cross method is used for the transfer of a single gene.
It helps in the recovery of whole parental type along with one additional gene.
If you selected for resistance to leaf rust among plants of F2 - F8 generations, then in F9 you can have plants that carry the resistance gene Lr9 in a homozygous state.
@ Lidiya Pershina ,
If the plants have been raised from F2 to F8 and then F9 generations, it means selfing has been practiced. Heterozygosity was maximum in F1 (all) plants i.e. 100%. In F2, homozygosity=50% (YY & ZZ) and Heterozygosity 50% (YZ).
In F3, homozygosity=75%, F4=87.5%. So homozygosity increases in every next (self) generation.
Therefore, even the plants of F9 generation contain resistant gene. The plants of (ZZ) genotype if any, will not carry the resistant gene.
M. C. Sidhu Lidiya Pershina Thank you for your help. As I found out, the plants have been self-pollinated so everything is clear now. Thanks again!
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