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.