Question

Androgenic haploids are useful in plant breeding so as
(a) to produce better hybrids.
(b) to produce homozygous organisms.
(c) to produce pathogen-free organisms.
(d) none of the above.

Answer 1

Hint: They can genetically generate such a male individual that has a double set of chromosomes and this is done with the help of certain chemicals that prevent spindle formation.

Complete answer:
Androgenic haploids are useful in plant breeding so as to produce homozygous organisms. Genetic principles that are applied to produce plants that are more useful to humans are considered as techniques of plant breeding.
Haploid plants are useful in breeding plants. They can be used to generate genetic homozygotes. This can be done by one generation doubling of chromosomes using colchicine. Spindle formation can be prevented by colchicine. Hence, the chromosome number can be easily doubled using it. The anther culture is used to produce haploids because anthers contain haploid microspores of pollen grains which can be used to generate new plants. These haploids are called androgenic haploids because they have been developed from male gamete producing spores, i.e., pollen grain or microspore. Haploid plants originate from gametes or gamete-like cells that do not go through fertilization but can still generate a viable individual. Therefore, haploids contain only the chromosome set found after meiosis in male or female gametes that is sperm cells or egg cells.

The Androgenesis process is divided into three main phases:
-overlapping phases: acquisition of embryogenic potential by stress involves repression of gametophytic development.
-dedifferentiation phase: dedifferentiation of the cells leads to the formation of multicellular structures contained by the exine wall.
-In the final phase, embryo-like structures are released out of the exine wall and pattern formation takes place.

So, the correct answer is, ‘to produce homozygous organisms’.

Note: -Haploid production through anther culture has been mentioned as androgenesis.
-In the anther culture technique, to produce haploids immature pollen is made to divide and grow into tissue.
-Some types of animals are haploid, such as male Hymenoptera for example, ants, bees, and wasps. This is a special genetic system called haplodiploidy.