Human Heredity 11th Edition by Michael Cummings

تمرين 26

Sunflowers with flowers 10 cm in diameter are crossed with a plant that has 20-cm flowers. The F1 plants have flowers 15 cm in diameter. In the F2 generation, 4 flowers are 10 cm in diameter and 4 are 20 cm in diameter. Between these are 5 phenotypic classes with diameters intermediate to those at the extremes.
A) Assuming that the alleles that contribute to flower diameter act additively, how many genes control flower size in this strain of sunflowers?
B) How much does each additive allele contribute to flower diameter?
C) What size flower makes up the largest phenotypic class?