In peas, the yellow color of the seeds A dominates over the green, and the smooth surface of the seeds B over the wrinkled b. When the flowers of yellow wrinkled peas were pollinated with pollen of green smooth peas, one half of the offspring was yellow smooth, the other half green smooth. Determine the genotypes of the parent plants.
In the offspring, according to the condition of the problem, one of the recessive traits was realized: half of the seeds of the obtained plants are green. This is possible only if the daughter plants are homozygous for the gene that determines the green color of the seeds – aa, therefore, the parent pea with yellow seeds for this trait is heterozygous for this trait – Aa.
No wrinkled seeds were obtained, therefore, peas with smooth seeds on the basis of the shape of the seeds are homozygous – BB.
Thus, the parent pea with yellow wrinkled seeds is Aavb; it produces sex cells Ab and ab.
The parent pea with green smooth seeds is aaBB, it produces germ cells of aB.
The offspring obtained from crossing such peas will look like this:
peas with yellow seeds and smooth shape (AaBb) – 50%;
peas with a smooth shape of green beans (aaBb) – 50%, which corresponds to the condition of the problem.
Answer: aaBB and Aabb.