What phenotypic proportions result from crossing TtYy (tall with yellow seeds) with Ttyy (tall with green seeds)?

When crossing a tall plant with yellow seeds (TtYy) with a tall plant with green seeds (Ttyy), we're examining a dihybrid cross where one parent is heterozygous for both traits and the other is heterozygous for height but homozygous recessive for seed color.

Gametes produced:

• TtYy produces: TY, Ty, tY, ty
• Ttyy produces: Ty, ty

Phenotypic proportions in offspring:

(a) Tall and green: The genotypes that produce tall and green phenotypes are TTyy, Ttyy. Using the Punnett square, the probability calculation shows 3/8 or 37.5% of offspring will be tall with green seeds.

(b) Dwarf and green: The genotypes that produce dwarf and green phenotypes are ttyy. The probability calculation shows 1/8 or 12.5% of offspring will be dwarf with green seeds.

Complete phenotypic ratio: 3 tall yellow : 3 tall green : 1 dwarf yellow : 1 dwarf green (3:3:1:1). This demonstrates the independent assortment of alleles and how different combinations of parental genes create variation in offspring.