Question

In bean plants, Mendel found that the allele for smooth seeds (S) is dominant, while the allele for wrinkled seeds (s) is recessive. Which of these Punnett squares shows crosses between two plants homozygous recessive for wrinkled seeds?

Answer 1

All offspring bean plants will be recessive homozygotes with wrinkled seeds.
If S is dominant allele responsible smooth seeds, and s is recessive allele responsible for wrinkled seeds, then genotypes will be:
SS - dominant homozygote with smooth seeds.
Ss - homozygote with smooth seeds.
ss - recessive homozygote with wrinkled seeds.

Cross between two recessive homozygotes (ss) will give all offspring with the same genotype (ss) as can be seen in the attached picture.