Question

Given below are the activities in the production of hybrid seeds of a crop. Find the correct group of activities-
(A). Effective generation and maintenance of male sterile parent
(B). Analysis of additive variance in the hybrid
(C). Production of \( F_1 \) seeds through natural or manual pollination
(D). Ensuring purity of the hybrid seeds through space or time isolation
Choose the correct answer from the options given below:

• A. (A), (B) and (C) only.
• B. (A), (B) and (D) only.
• C. (A), (C) and (D) only.
• D. (B), (C) and (D) only.

Hint:

Hybrid seed production is a practical field operation focused on maintaining maternal male sterility, ensuring cross-pollination, and isolating the field to prevent contamination.
Theoretical quantitative genetic analyses (like partitioning additive variance) are not part of seed production.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Hybrid seed production relies on crossing two distinct parental lines to produce \( F_1 \) progeny that express heterosis.
To make this process commercially viable, breeders must prevent self-pollination of the maternal parent, facilitate cross-pollination by the paternal parent, and maintain high genetic purity of the harvested \( F_1 \) seeds.

Step 2: Detailed Explanation:
Let us analyze each activity listed:
- Activity (A) is correct: To prevent self-pollination in the female parent, male sterility systems (such as Cytoplasmic Male Sterility, CMS, or Genic Male Sterility, GMS) are widely used.
Generating and maintaining these male sterile lines (A-lines) alongside their maintainer lines (B-lines) is essential for successful hybrid seed production.
- Activity (B) is incorrect: The analysis of additive genetic variance is a tool used during population improvement or parent selection.
Once the parents have been selected and the hybrid is being produced, analyzing genetic variance is no longer an activity of seed production.
Moreover, hybrids primarily exploit non-additive genetic variance (dominance and epistasis).
- Activity (C) is correct: Commercial \( F_1 \) seed is produced by crossing the female parent (male sterile) and the male parent (pollen donor) through hand-pollination (in crops like cotton or cucurbits) or natural wind/insect pollination in designated row ratios (in crops like maize, rice, or pearl millet).
- Activity (D) is correct: To prevent contamination from foreign pollen, hybrid seed production plots must be isolated from other fields of the same crop using physical distance (space isolation) or staggered planting dates (time isolation).
Therefore, activities (A), (C), and (D) are correct, while (B) is incorrect.

Step 3: Final Answer:
The correct option is (C), which contains (A), (C) and (D) only.