Question

The kernel color in wheat is a continuous trait determined by two additive genes, each with two alleles, that equally contribute to kernel color determination. The red kernels are determined by two genes and two dominant alleles (R₁ R₂), and white kernels are determined by two recessive alleles at the same two genes (r₁ r₂). The duplicate dominant alleles R₁ and R₂ contribute equally to kernel color and cumulatively control the intensity of the red kernel phenotype. Both these alleles are dominant over the recessive white alleles r₁ and r₂. A true breeding red plant and true breeding white plant are crossed, and the resulting F₁ progeny are selfed.

What is the expected phenotypic ratio of the kernel progeny of the F₂ offspring?

Answer 1

The expected phenotypic ratio of the F₂ offspring's kernel progeny is 1 red: 2 pink: 1 white. The red allele is dominant over the white allele, but the heterozygous genotype results in a blend of the two phenotypes, producing pink kernels.

Step-by-step explanation:

The expected phenotypic ratio of the kernel progeny of the F₂ offspring can be determined by using a Punnett square.

In the F₁ generation, the true breeding red plant (RR) is crossed with the true breeding white plant (rr), resulting in all heterozygous red offspring (Rr). When the F₁ offspring self-fertilize in the F₂ generation, the expected phenotypic ratio is 1 red: 2 pink: 1 white.

This is because the red allele is dominant over the white allele, but the heterozygous genotype results in a blend of the two phenotypes, producing pink kernels.