Question

The breeding method usually used to produce the nucleus seeds of a variety of cereal crops is -

• A. Ear-to-row method
• B. Backcross method
• C. Apomixis
• D. Advanced-backcross method

Hint:

The "Ear-to-row" or "Head-to-row" method is the standard quality-control method for self-pollinated cereals. Growing each selected head in its own row allows the breeder to easily spot and discard any family lines showing genetic mutations or physical contamination.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Nucleus seed is the highest class of physically and genetically pure seed, produced under the direct supervision of the originating plant breeder.
For self-pollinated cereal crops (such as wheat, rice, and barley), the primary objective is to maintain absolute trueness-to-type by eliminating any off-types or genetic mutations.

Step 2: Detailed Explanation:
The standard, globally accepted breeding method used to produce and maintain nucleus seeds in self-pollinated cereals is the Ear-to-row (also known as head-to-row or plant-to-row) selection method.
This procedure consists of the following steps:
1. A large number of healthy, true-to-type individual ears or heads (typically 200–500) are selected from a certified crop field during maturity.
2. Each selected ear is threshed separately, and its seeds are sown in a single individual row (ear-to-row progeny plot).
3. These individual progeny rows are evaluated throughout the growing season for morphological uniformity and trueness-to-type.
4. Any progeny row that displays any off-types, disease susceptibility, or heterogeneity is completely discarded.
5. The remaining, highly uniform and authentic progeny rows are harvested and bulked together to constitute the fresh nucleus seed stock.
Therefore, the Ear-to-row method is the correct answer.

Step 3: Final Answer:
The breeding method usually used to produce nucleus seeds in cereals is the Ear-to-row method.