In common wheat kernel color varies from red to white, the genes for kernel color acting additively. Phenotypic classification of segregating progenies between red and white kernel varieties is possible.

a) A cross is made between a dark red kernel R1R1R2R2 and a white kernel r1r1r2r2 variety. Give the genotype and phenotype of the F1 and the F2 genotypes and ratios for the phenotypes dark red, medium dark, medium, light and white.

b) From a second cross between red and white varieties, 1/64 of the F2 progeny have red and 1/64 white kernels. How many allele pairs control kernel color in this cross?