In tomatoes, the round shape of the fruit dominates over the oval shape. By crossing a homozygous plant

In tomatoes, the round shape of the fruit dominates over the oval shape. By crossing a homozygous plant with round fruits with a plant producing oval fruits, F1 hybrids of 48 plants were obtained, from the self-pollination of which 192 F2 plants were obtained. a) how many types of gametes can be formed in plants with oval fruits? b) How many F1 plants will have round fruits? c) how many F2 plants will be dominant homozygotes? d) how many F2 plants will have round fruits? e) how many different genotypes will there be in F2?

Let’s designate the gene for the round shape of tomatoes as S, and the gene for their oval shape as s.

Homozygous round-fruit tomato – SS, it produces S.

Tomatoes with oval fruits will be homozygotes – ss, which is necessary for this phenotype to be realized. They will also produce the same type of germ cells – s.

All 48 F1 plants will be round-fruit tomatoes with a heterozygous Ss genotype. Such hybrids are capable of producing germ cells of two types – s and S.

As a result of their self-pollination in F2, we get the following options:

tomatoes – homozygotes with round fruit (SS) – 25%;

tomatoes – heterozygotes with a round fruit (Ss) – 50%;

tomatoes – homozygotes with oval fruit (ss) – 25%.

a) 1 type of gametes;

b) all 48 plants;

c) 192 * 0.25 = 48 plants;

d) 192 * 0.75 = 144 plants;

e) 3 genotypes.