In pumpkin, white fruit color dominates over yellow, and disc-shaped fruit over spherical.

In pumpkin, white fruit color dominates over yellow, and disc-shaped fruit over spherical. A pumpkin plant with white disc-shaped fruits was crossed with a plant having white globular fruits. The offspring produced: 38 plants with white disc-shaped fruits; 36 – with white spherical; 13 – with yellow disc-shaped; 12 – with yellow spherical. Determine the genotypes of the parent plants.

Let’s designate the gene for white color of pumpkin fruits as M, the gene for yellow color – m. Let’s designate the gene for the disc-shaped form of pumpkin fruits as P, and the spherical shape as p.

Since there are plants in the offspring that exhibit both recessive traits, it should be concluded that those pumpkins are heterozygous that show traits that are classified as dominant.

Let us denote, according to the above, pumpkins with white disc-shaped fruits as MmPr. They will produce mr, mr, mr and mr sex cells.

Let’s designate pumpkins with white globular fruits as Mmrr, and the germ cells produced by them as Mp and mr.

The offspring will look like this:

pumpkins with white spherical fruit (2Mmrr, Mmrr);

pumpkins with a white disc-shaped fruit (MMPr, 2MmRr);

pumpkins with a yellow ball-shaped fruit (mmrr);

pumpkin with a yellow disc-shaped fruit (mmPr).

The resulting splitting of the 3: 3: 1: 1 type corresponds to the numerical values ​​obtained in the problem statement.

Answer: MmRr and Mmrr.