Question

What is male sterility?

Answer 1

Hint: The male sterility is found in plants. Male sterility is used in crop plants for hybrid breeding. This avoids the need of removing the pollen in a flower in the absence of female reproductive organs for cross-pollinated species. Thus this encourages cross-breeding which produces only hybrid seeds even under natural conditions.

Complete Answer:
Male sterility is the inability to produce the functional pollen which results in the failure of the formation of microspores, stamens or gametes.
There are two types of male sterility:
- Structural male sterility in which male flowers are deformed and completely absent.
- Functional male sterility in which there is good and feasible pollen trapped in a situation unable to split open to release the seeds when ripe. Cytoplasmic male sterility is used in agriculture to facilitate the production of hybrid seed. Hybrid seed is produced from a cross between two genetically different lines; such seeds usually result in larger, more vigorous plants.

Note: The male sterility in plants can be caused either by mitochondrial genes which are coupled with nuclear genes or by only nuclear genes. The common male sterility in flowering plants is nuclear male sterility. But the application of nuclear male sterility in seed production and hybrid breeding is limited due to the inability to breed a pure male sterile for hybrid seed production which will be used commercially. Male sterility is widely observed in crops such as maize, sunflower, rice and wheat. Male sterility is easy to identify among the plants because a large number of pollen grains will be produced from the hybrid seeding.