Question

A dihybrid plants on self polination produced 400 phenotypes with 9 types of genotypes. the number of seeds having genotype RrYy is​

Answer 1

Answer:

The self pollination of a dihybrid plant yields the genotypic ratio of 1 TTRR : 2 TTRr : 1 TTrr : 2 TtRR : 4TtRr : 2 Ttrr : 1ttRR : 2 ttRr : 1 ttrr. The ratio of genotype TtRr is 4/16. Hence, out of total 400 phenotypes, number of seeds having TtRr genotype will be 4/16x400 = 100. Option "B" is correct.

F 1 generation :  TtRr  x  TtRr  

Gametes :

TtRr  -->

TtRr TR    Tr tR tr

TR TTRR    TTRr   TtRR  

TtRr

Tr TTRr    TTrr TtRr Ttrr

tR TtRR   TtRr ttRR     ttRr

tr TtRr   Ttrr ttRr ttrr