Two pairs of independently segregating genes with two allele

Two pairs of independently segregating genes with two alleles each A/a and B/b, determine plant height additively in a population. The homozygote AABB is 60 cm tall, and the homozygote aabb is 20 cm tall. If each gene contributes an equal amount to the height what would would be the expected heights in the progeny when a plant with genotype AaBb is crossed to a plant with genotype Aabb? 1/4-60cm, 1/4-50cm, 1/4-40cm, 1/4 30cm 1/8-50cm, 3/8-40cm, 3/8-30cm, 1/8-20cm 1/4-50cm, 1/2-40cm, 1/4-30cm 1/8-60cm, 3/8-50cm, 3/8-40cm, 1/8-30cm 1/4-60cm, 1/2-50cm, 1/4-40cm

Solution

Cross between

AaBb X Aabb

If the height of plant AABB is 60cm and aabb is 20 cm

then A or B allele will contribute 15cm and \'a\' or \'b\' allele will contribute 5 cm

So the genotypes resulting from the above cross are

1/8th will be 50cm(AABb), 3/8th would be 40 cm( 2AaBb, 1AAbb) , 3/8th would be 30 cm ( 2Aabb, 1aaBb)and 1/8th would be 20cm(aabb)

	Ab	ab
AB	AABb	AaBb
Ab	AAbb	Aabb
aB	AaBb	aaBb
ab	Aabb	aabb