Question

Given below are two statements, one is labeled as Assertion (A), and the other one is labeled as Reason (R).
Assertion (A): The seeds obtained from a hybrid can not be used for raising the next crop, and need to produce fresh hybrid seeds for sowing in the next season.
Reason (R): Selfing, segregation, and inbreeding decrease heterosis in the seeds of hybrid crops.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

Remember:
\( F_1 \) Hybrids = Maximum heterozygosity and uniformity.
\( F_2 \) Generation = Genetic segregation and reduced heterozygosity, leading to a loss of heterosis and crop uniformity.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
\( F_1 \) hybrid varieties are developed by crossing two genetically distinct, homozygous inbred lines.
These hybrids exhibit maximum heterozygosity and phenotypic uniformity, resulting in high vigor and yield due to heterosis (hybrid vigor).

Step 2: Detailed Explanation:
Let us analyze both statements:
1. Analysis of Assertion (A): Farmers cannot save and replant seeds harvested from an \( F_1 \) hybrid crop to raise the next season's crop.
Doing so results in a severe reduction in yield, a loss of crop uniformity, and staggered maturity.
Farmers must purchase fresh \( F_1 \) hybrid seeds every season to maintain high yields. Thus, Assertion (A) is correct.
2. Analysis of Reason (R): According to Mendelian genetics, self-pollination (selfing) of a highly heterozygous \( F_1 \) hybrid leads to genetic segregation in the \( F_2 \) generation.
This segregation significantly reduces heterozygosity, halving the percentage of heterozygous loci with each generation of selfing.
As heterozygosity decreases, the beneficial effects of heterosis are lost, and the plants undergo inbreeding depression.
This genetic segregation and loss of heterosis directly explain why saved hybrid seeds perform poorly and cannot be reused.
Therefore, both statements are correct, and Reason (R) is the correct genetic explanation for Assertion (A).

Step 3: Final Answer:
Both (A) and (R) are correct, and (R) is the correct explanation of (A), corresponding to option (A).