Question

Haploids can be artificially produced by -
A. Colchicine doubling
B. X-ray treatment
C. Pollen culture
D. Distant hybridization
E. Infrared radiation
Choose the correct answer from the options given below :

• A. A, B, and C Only
• B. B, C, and E Only
• C. A, D, and E Only
• D. B, C, and D Only

Hint:

The two most important methods for haploid production are anther/pollen culture (androgenesis) and ovary/ovule culture (gynogenesis). Distant hybridization leading to chromosome elimination is another key method, especially in cereals.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The question asks to identify the valid techniques used for the artificial production of haploid plants.
Step 2: Detailed Explanation:
A. Colchicine doubling: Colchicine is used to double the chromosome number, for example, to convert a haploid into a homozygous diploid. It does not produce haploids. (Incorrect)
B. X-ray treatment: Irradiating pollen with X-rays can destroy the genetic material in the male gamete. If this pollen is used for pollination, it can stimulate the egg cell to develop parthenogenetically into a haploid embryo. This is a valid, though less common, method. (Correct)
C. Pollen culture: Also known as anther/microspore culture, this is a standard and widely used technique where immature pollen grains (microspores) are cultured in vitro to develop into haploid plants (androgenesis). (Correct)
D. Distant hybridization: Crossing two distantly related species (e.g., wheat with maize, or barley with Hordeum bulbosum) can lead to the selective elimination of the chromosomes of one parent during early embryo development, resulting in a haploid plant of the other parent. (Correct)
E. Infrared radiation: This is a form of electromagnetic radiation associated with heat and is not used for inducing haploidy. (Incorrect)
Step 3: Final Answer:
The correct techniques listed are X-ray treatment, Pollen culture, and Distant hybridization.