In one of his experiments with pea plants Mendel observed that when a pure tall pea plant is crossed with a pure dwarf pea plant, in the first generation, F1 only tall plants appear.
(a) What happens to the traits of the dwarf plants in this case?
(b) When the F, generation plants were self-fertilised, he observed that in the plants of the second generation, F2 both tall plants and dwarf plants were present. Why did it happen? Explain briefly. (Delhi 2016)

Mendel’s monohybrid cross showed that only one of two contrasting traits shows itself in the offspring of the first generation. As a result, it can be determined that the characteristic expressed in the F₁ generation are dominant and the trait that does not is recessive. The dominant gene or allele and the recessive gene or allele are the genes that control the dominant trait and the recessive trait, respectively.

Although the dominant trait is expressed in F₁ progeny, the genes for both the dominant and recessive traits are also present. Only when recessive genes are found in homozygous conditions does the recessive characteristic have a chance to show in the following generation.

This can be illustrated by the given cross:

(b) The occurrence of a suppressed recessive trait in F₂ generation individuals in a Mendelian cross shows that recessive traits’ characteristics are kept even when they are not expressed. Both parental features were expressed in a clear ratio in the F₂ generation when the F₁ generation plants were permitted to self-fertilize. By selfing the gametes obtained in the F₁ generation, the provided cross could account for this.