Question

Reciprocal crossing is possible in the following mating design in which both the parents are known to the breeders. ______________

• A. Hierarchical design
• B. Tester design
• C. Full diallel design
• D. Poly cross design

Hint:

Diallel = "All-to-all." It is the only design that gives the full genetic picture, including maternal and reciprocal effects.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question focuses on "mating designs"—mathematical schemes for crossing trees to determine their breeding values. It specifically asks about a design that allows for "reciprocal crosses."

Step 2: Detailed Explanation:

• Definition of Reciprocal Cross: A reciprocal cross involves making a cross between two individuals in both directions: using Individual A as the male and B as the female ($A \times B$), and then using B as the male and A as the female ($B \times A$). This helps determine if there are any maternal effects.

• Full Diallel Design: In a full diallel, every individual in a group of $n$ parents is crossed with every other individual (including selfs and reciprocals). It is the most comprehensive mating design but requires the most work.

• Comparison:
- Tester design: Crosses many males to a few fixed "testers"; doesn't naturally include reciprocals.
- Hierarchical (Nested): Each female is mated to a unique set of males; no reciprocal crosses possible.
- Poly cross: Wind pollination among a set of clones; only the mother is known, and father is a random mixture.

Step 3: Final Answer:
Reciprocal crossing is a feature of the Full diallel design.