Two genes of a flower, one controlling blue (b) versus white (w) petals and the other controlling round (r) versus oval (o) stamens, are linked and are 10 map units apart. you cross a homozygous blue-oval plant with a homozygous white-round plant. The resulting f1 progeny are crossed with homozygous white-oval plants, and 1,000 f2 progeny are obtained. How many f2 plants of each of the four phenotypes do you expect?

The offspring genotype in F2 generation is -

bwoo: wbor: worw: wwoo

So its ratio is

4:4:4:4

1:1:1:1

Thus number of individual in each genotype group out of 1000 is 250

Explanation:

Given -

homozygous blue-oval plant is crossed with homozygous white-round plant

Genotype of homozygous blue-oval plant - bboo

Genotype of homozygous white-round plant - wwrr

The ofspring produced in F1 generation will have genotype - bowr

In F2 generation, "bowr" is crossed with homozygous white-oval plants "wwoo"

The following offspring are produced -

bwor - bo, br, wr, wo

wwoo - wo, wo, wo, wo

bo br wr wo

wo bwoo wbor worw wwoo

wo bwoo wbor worw wwoo

wo bwoo wbor worw wwoo

wo bwoo wbor worw wwoo

The offspring genotype is -

bwoo: wbor: worw: wwoo

So its ratio is

4:4:4:4

1:1:1:1

Thus number of individual in each genotype group out of 1000 is 250