Question

With the help of an example justify the following statement: "A trait may be inherited, but may not be expressed".

Answer 1

A monohybrid cross between two pure breeding varieties (round, RR and wrinkled rr seeds) obtains all progeny with round seeds (Rr) in $F_1$ generation. Selfing of $F_1$ hybrids obtains progeny with round and wrinkled seeds in 3: 1 ratio respectively. It shows the law of dominance allowed only dominant factor (round seed) to be expressed in $F_1$ hybrid, although it inherited the recessive trait (wrinkled seed) from parents which was then expressed in $F_2$ generation.