Question

An example of 'primary introduction' of crop varieties in plant breeding in India is -

• A. Sonalika
• B. Kalyan Sona
• C. Sonora 64
• D. PBW343

Hint:

Primary introductions are the fastest way to introduce new traits into agricultural production, but they require the introduced crop to be pre-adapted to the local day length and climate.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Plant introduction is the process of introducing a plant genotype or variety into a new geographic area where it was not previously grown.
It is classified into primary introduction and secondary introduction based on how the introduced material is utilized.

Step 2: Detailed Explanation:
Let us analyze the differences between primary and secondary plant introductions:
1. Primary Introduction: This occurs when an introduced variety is well-suited to the new environment and is released directly for commercial cultivation without any genetic modification, selection, or hybridization.
In India, the semi-dwarf wheat varieties Sonora 64 and *Lerma Rojo 64A* were introduced directly from Mexico (developed by Norman Borlaug at CIMMYT) during the mid-1960s.
Because they performed exceptionally well, they were released directly to farmers, serving as classic examples of primary introduction that helped launch the Green Revolution.
2. Secondary Introduction: This occurs when the introduced variety is modified through selection or crossed with local varieties to develop a new cultivar.
For example, *Sonalika* and *Kalyan Sona* are secondary introductions, as they were selected from segregating lines introduced from Mexico to improve grain color and disease resistance.
*PBW343* is a modern wheat variety developed later through intensive cross-breeding programs in India.

Step 3: Final Answer:
The example of primary introduction of wheat in India is Sonora 64, which corresponds to option (C).