Genetics: The Genotype and Phenotype Ratios in the F2 Generation From a Cross Between a Tall and a Short Parent Plant.

A tall parent plant and a short parent plant mate. if tall F1 plants self-pollinate, what will the F2 plants look like?

75% will be tall and 25% will be short

If a tall parent plant (TT) and a short parent plant (tt) mate, their offspring in the F1 generation will all be tall because the dominant allele (T) is expressed in heterozygous individuals (Tt). Therefore, all F1 plants will have the genotype Tt and phenotype tall.

If the tall F1 plants self-pollinate to produce the F2 generation, the offspring will have a genotype ratio of 1:2:1 (TT:Tt:tt) and a phenotype ratio of 3:1 (tall:short).

This is because during meiosis, the Tt F1 plants can produce gametes with either the T allele or the t allele. Therefore, the possible genotypes for the offspring in the F2 generation are TT, Tt, and tt.

The TT genotype will result in a tall phenotype, the tt genotype will result in a short phenotype, and the Tt genotype will result in a tall phenotype (due to the expression of the dominant allele, T).

Therefore, the F2 generation will consist of 25% TT (tall), 50% Tt (tall), and 25% tt (short) genotypes, and 75% tall and 25% short phenotypes.

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