Question

suppose you have monohybrid pea plants in your garden and find that they produce round seeds to wrinkled seeds in the ratio of 3:1 if the alleles are designated R and r, respectively, what are the probable genotypes of the wrinkled seeds produced by your plants

Answer 1

The answer is rr. In a monohybrid cross, the phenotypic ratio is 3:1 for dominant trait to recessive trait. Since the ration is 3:1 for round seeds to wrinkled seeds, we can conclude that round seed is the dominant trait. Let R be a dominant allele for round seed and r be a recessive allele for wrinkled seed. The genotypes will be: RR (dominant homozygote with round seeds), Rr (heterozygote with round seeds), and rr (recessive homozygote with wrinkled seeds. Thus, only genotype rr is the genotype of the wrinkled seeds.