Question

If red flowered plant is crossed with white flowered plants of the above species is crossbreeded the genotypic and phenotypic ratio will be respectively as

Answer 1

Answer:

Since the F

2

generation ratio of red and white colour flower is 60:20 (3:1), the allele for red flower is completely dominant over that of white colour flower. If the red flower allele is denoted by R and that of white colour is denoted by r, the genotype of heterozygous red flowered plant will be Rr. This heterozygous red flowered plant will produce two types of gametes R and r. Selfing of heterozygous red flowered plants produce red and white colour flowers in 3:1 ratio. Option A (72:24) also show the same ratio. Hence, the correct option is A.

Gametes :

Rr --->

Rr R r

R RR

red Rr

red

r Rr

red rr

white