In watermelons, the round shape of the fruit (A) dominates over the elongated one, and the green

In watermelons, the round shape of the fruit (A) dominates over the elongated one, and the green color (B) over the striped one. Homozygous plants with round green fruits were crossed with a plant with elongated striped fruits. What will be the shape and color of the fruits of the first and second generation watermelon? Determine the genotype cleavage in the second generation.

Let us write down the genotypes of the parent plants according to the designations introduced in the problem statement. Homozygous watermelons with round green fruits will be AABB, such watermelons will produce germ cells of the same type – AB.

Elongated striped fruits of watermelons can appear only in plants with the aavv genotype, since homozygosity is a necessary condition for the realization of these traits. Such watermelons will produce sex cells ab.

The first generation of watermelons will be genotypically and phenotypically homogeneous – AaBb, round green watermelons. Such watermelons, in turn, will produce sex cells AB, ab, Ab and aB.

The second generation of watermelons will be diverse and represented by the following plant varieties:

round green watermelons (ААВВ, 4 АаВb, 2 АаВВ, 2 ААВb);

elongated striped watermelons (aabb);

spherical striped watermelons (2 aaBb, aaBB);

elongated green watermelons (2 AAbb, Aabbb).

Answer: 9: 3: 3: 1.