A homozygous plant with 20-cm diameter flowers is crossed with a homozygous plant of the same species with 50-cm diameter flowers. The F1 flowers all have 35-cm diameter flowers. In the F2 generation of 192 plants, 3 plants have flowers that are 20cm in diameter, and 3 have flowers that are 50cm in diameter. The remaining 186 plants have flowers of a range of sizes in between. All plants were grown and crossed in a constant laboratory setting.
a) Assuming all alleles involved act additively, how many genes control flower size in this plant?
b) Calculate and graph the frequency distribution of flower diameters you should have obtained in the F2 generation.
c) Calculate and graph the frequency distribution you would expect for a backcross between the F1 generation plants and the large flowered parent.