Mendel crossed peas having round seeds and yellow cotyledons

Mendel crossed peas having round seeds and yellow cotyledons (seed leaves) with peas having wrinkled seeds and green cotyledons. All the F₁ plants had round seeds with yellow cotyledons. Based on this cross, what is the probability that an organism in the F₂generation will have round seeds and green cotyledons and be true breeding?

Solution

From the F1 generation we have the information that all round seeds with yellow cotyledons are produces, and from Mendel\'s Pea plant experimentation we know that yellow cotyledon and round seed both is the dominat trait. Also genotypically we can write as parents RRYY(round seed and yellow cotyledon) * rryy( wronkle seed and green cotyledon). In F1 progeny all are having RrYy trait as (round seed and yellow cotyledon).

Upon turning to second generation we know that the cross between the F1 progeny of heterozygous indivisual we can get a phenotypic ratio of 9:3:3:1. That is 9 round and yellow as true breeds, like passed on traits as like parents. So here the probablity would be = no of true breeds/ no of total occurances = 9/16.