Question

A true breeding pea plant, homozygous for inflated green pods is crossed with another pea plant with constricted yellow pods (ffgg). What would be the phenotype and genotype of F₁ and F₂ generations? Give the phenotypic ratio of F₂ generation.

State the generalisation proposed by Mendel on the basis of the above mentioned cross.

Answer 1

Let F = inflated (dominant), f = constricted, G = green (dominant), and g = yellow. Parents: true-breeding inflated green FFGG × constricted yellow ffgg. F₁: all FfGg, inflated green. Selfing F₁ (FfGg × FfGg) produces F₂ phenotypes in the ratio 9 inflated green : 3 inflated yellow : 3 constricted green : 1 constricted yellow. The F₂ genotypes arise from FfGg producing FG, Fg, fG and fg gametes. Mendel’s law of independent assortment states that the inheritance of one gene pair is independent of the other, when the genes assort independently.