Question

Phenotypic superiority of hybrid over either of its parents in one or more traits is termed hybrid vigour. Suppression of expression of recessive harmful genes occurs in heterozygotes.

• A. If both assertion and reason are true and reason is the correct explanation of asseration
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

If both assertion and reason are true and reason is the correct explanation of asseration

Answer 2

Plant breeding exploits the phenomenon of hybrid vigour or heterosis. It is the phenotypic superiority of the hybrid over either of its parents in one or more traits. These hybrids generally have greater strength and resistance to disease and larger life span than either parents. This may be due to suppression of expression of harmful recessive genes that are expressed only in homozygous conditions.