Question

The main advantage of haploid plants in crop breeding program is:

• A. High homozygosity
• B. High heterozygosity
• C. Null mutations
• D. High allelic expression

Hint:

Doubled Haploids = Instant Pure Lines. It turns a 7-year waiting game into a 1-year process by ensuring every gene is homozygous.

Answer 1

The Correct Option is A

Concept: Haploid plants ($n$) are vital in plant breeding because they contain only one set of chromosomes. When their chromosome number is doubled (using agents like colchicine), they become "doubled haploids" ($2n$).

Step 1: Understanding Homozygosity.
In traditional breeding, achieving a "pure line" (where both alleles for every gene are identical) requires several generations of self-pollination. However, because a doubled haploid is created by duplicating a single set of chromosomes, every single gene pair in the resulting plant is automatically identical. This state is known as high homozygosity.

Step 2: Application in Breeding.
This process allows breeders to produce stable, true-breeding lines in a single generation rather than 6 or 7 years. These lines can then be evaluated for superior traits or used as parents for hybrid seed production.

Step 3: Conclusion.
The immediate attainment of 100% homozygosity is the single most significant advantage of using haploids in crop improvement programs.