Analysis of Statements on Crop Varieties

Assertion (A) Analysis: Performance of Synthetic Varieties

The assertion states that the performance of synthetic varieties is better than single or double cross hybrids. This statement is generally considered incorrect in plant breeding.

• Synthetic varieties are developed from multiple parent lines selected for their general combining ability (GCA).
• Double cross hybrids, in particular, are known to exhibit higher performance due to the exploitation of both general combining ability (GCA) and specific combining ability (SCA), leading to greater heterosis.
• Therefore, double cross hybrids typically outperform synthetic varieties.

Reason (R) Analysis: Combining Ability Exploitation

The reason states that synthetics exploit only general combining ability (GCA) while hybrids exploit GCA and specific combining ability (SCA). This statement is correct.

• Synthetics: Their development primarily focuses on improving the average performance of the population by selecting parents with good GCA.
• Hybrids (Single and Double Cross): These are specifically bred to capitalize on the superior performance resulting from the unique combination of parents, which involves exploiting both GCA and, crucially, specific combining ability (SCA). Double crosses further enhance this by combining two superior single crosses.

Conclusion

Based on the analysis:

• Assertion (A) is incorrect because synthetic varieties generally do not outperform advanced hybrids like double crosses.
• Reason (R) is correct as it accurately describes the genetic basis (GCA vs. GCA and SCA) for the performance of synthetics and hybrids.

Since (A) is incorrect and (R) is correct, the most appropriate choice is that (A) is not correct but (R) is correct.