93. Which one of the following genes can be used to generate male sterile crop plants?
A. Barnase
B. Bar
C. Lectinase
D. Chalcone Synthase

Detailed Explanation:

In agricultural biotechnology, the creation of male sterile plants is an essential technique, especially in hybrid seed production. Male sterility is a condition in plants where they are unable to produce viable pollen, preventing self-pollination and facilitating controlled cross-pollination. This approach is commonly used to produce hybrid seeds, which are often more vigorous and higher-yielding than non-hybrid seeds.

Key Genes Used for Male Sterility:

1. Barnase Gene:

   • Barnase is a gene that encodes a ribonuclease enzyme, which specifically targets and degrades RNA. In the context of male sterility, the Barnase gene is often used in conjunction with a promoter that ensures it is expressed only in the anther tissues (the male reproductive organs of a plant).

   • The expression of Barnase leads to the destruction of RNA in the pollen-producing cells, effectively preventing the plant from producing functional pollen and thus rendering it male sterile.

   • This gene is widely used in crop breeding programs to ensure controlled pollination for hybrid seed production.

2. Bar Gene:

   • The Bar gene comes from the bacteria Streptomyces and confers resistance to the herbicide phosphinothricin. While it is useful for selecting genetically modified plants, it does not play a role in inducing male sterility.

3. Lectinase Gene:

   • The Lectinase gene is involved in encoding enzymes that degrade lectins (carbohydrate-binding proteins), but it does not have a direct application in creating male sterile plants.

4. Chalcone Synthase Gene:

   • The Chalcone Synthase gene is a key enzyme in the flavonoid biosynthetic pathway, which influences the pigmentation of plants. While it is important for other aspects of plant biology, it is not used for generating male sterile plants.

Correct Answer:

A. Barnase