Question

A cross is made between true-breeding lines of pea plants with axillary and terminal flowers. If 1240 progeny are obtained, what is the ratio between homozygous plants and heterozygous plants of $F_2$ progeny?

• A. 3:1
• B. 1:2:1
• C. 1:1
• D. 1:1:2

Answer 1

The correct option is C

1:1

Out of $F_2$ progeny in monohybrid cross ${\frac{1}{4}}^{th}$ are homozygous dominant, $\frac{1}{2}$ are heterozygous dominant and ${\frac{1}{4}}^{th}$ are homozygous recessive. Thus calculating the fraction of homozygous progeny is $\frac{1}{4}$ + $\frac{1}{4}$ = $\frac{1}{2}$. And the other $\frac{1}{2}$ being heterozygous. Therefore the ratio between all the homozygous and heterozygous plants is 1:1.