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

wobwoowborworwwwoo

wobwoowborworwwwoo

wobwoowborworwwwoo

wobwoowborworwwwoo

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

telophase and anaphase