Three different pure-breeding strains of corn that produce ears with white kernels were crossed to each other. In each case, the F1 plants were all red, while both red and white kernels were observed in the F2 generation in a 9:7 ratio. These results are shown in the data table below:
.......................................... F1......................... F2
white-1 x white-2 ..............red .........................9 red : 7 white
white-1 x white-3 ..............red .........................9 red : 7 white
white-2 x white-3 ............. red .........................9 red : 7 white
a. How many genes are there? How many alleles does each gene have? What type of gene interaction does the ratio in the F2 indicate?
b. Define your symbols and show the genotypes for the pure-breeding strains white-1, white-2 and white-3.
c. Show a cross between white-1 and white-2. Show the genotypes and phenotype of the F1 progeny. Show the genotypic classes, corresponding phenotypes, and the ratios of the F2.