Question

Suppose that in barley plants, the allele for tall stalks is dominant over short stalks and the allele for wide leaves is dominant over thin leaves. what would be the best way to determine the genotype of a barley plant with a tall stalk and wide leaves?

Answer 1

Preform a testocross with a barley plant that has a short stak and thin leaves

Answer 2

The answer is to perform a self-fertilization of the barley plant. The plant can either be homozygous dominant or heterozygous dominant to have the stipulated traits. Therefore, such as cross will determine the genotype of the plant. If the barley is homozygous dominant, it will produce all offspring who have wide leaves and tall stalks. If the plant is heterozygous dominant, them 25% of the offspring will have thin leaves and short stalk.

The attached punnet square demonstrates this; assume that the allele for leaf type is represented by B (dominant) and b (recessive); while that of stalk length is denoted by T (dominant) and t (recessive).