Question

What is the phenotypic ratio in the F₂ generation when crossing AaBbCc × AaBbCc in wheat kernel colour?

Options

• 15 Red : 1 White

• 63 Red (various shades) : 1 White

• 27 Dark : 9 Medium : 3 Light : 1 White

• 9 Red : 3 White : 4 Intermediate

Answer 1

In the classic Nilsson-Ehle wheat kernel colour experiment with three gene pairs, the F₂ ratio is 63 Red (in various shades) : 1 White. This occurs because only the triple recessive genotype (aabbcc) produces white kernels, while all other combinations produce shades of red, demonstrating the continuous variation characteristic of polygenic inheritance.