Question:
Given below are two statements regarding combining ability, where it is the ability of parents or crosses to combine among each other during hybridization process which results in transmission of desirable genes or characters to the their progenies.
Statement I: SCA is attributable through half‐sib families where in one parent is known.
Statement II: Where GCA is attributable due to full sib families.
In light of the above statements, choose the most appropriate answer from the options given below
Given below are two statements regarding combining ability, where it is the ability of parents or crosses to combine among each other during hybridization process which results in transmission of desirable genes or characters to the their progenies.
Statement I: SCA is attributable through half‐sib families where in one parent is known.
Statement II: Where GCA is attributable due to full sib families.
In light of the above statements, choose the most appropriate answer from the options given below
Statement I: SCA is attributable through half‐sib families where in one parent is known.
Statement II: Where GCA is attributable due to full sib families.
In light of the above statements, choose the most appropriate answer from the options given below
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Mnemonic: Generous (GCA) performance is for the whole Half-sib (H) family. Special (SCA) performance is for a specific Full-sib (F) pair.
Updated On: Aug 7, 2026
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
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The Correct Option is B
Solution and Explanation
Step 1: Understanding the Question:
The question asks to evaluate two statements about General Combining Ability (GCA) and Specific Combining Ability (SCA). These are statistical concepts used in breeding programs to evaluate parent trees and their hybrid combinations.
Detailed Explanation:
• General Combining Ability (GCA): This is the average performance of a parent in a series of crosses. It is associated with additive genetic effects, which are highly inheritable. GCA is traditionally estimated using half-sib families (progenies where only one parent is known/controlled, like in open-pollinated seed orchards). Therefore, Statement II is incorrect as it links GCA to full-sibs.
• Specific Combining Ability (SCA): This refers to cases where certain hybrid combinations perform better or worse than expected based on the average of the two parents (GCA). It is associated with non-additive genetic effects (dominance and epistasis). SCA is estimated using full-sib families (where both parents are known and controlled). Therefore, Statement I is incorrect as it links SCA to half-sibs.
• Conclusion: The two statements have effectively swapped the definitions/methods of measurement for GCA and SCA.
Step 2: Final Answer:
Both Statement I and Statement II are incorrect because GCA is estimated via half-sibs and SCA via full-sibs.
The question asks to evaluate two statements about General Combining Ability (GCA) and Specific Combining Ability (SCA). These are statistical concepts used in breeding programs to evaluate parent trees and their hybrid combinations.
Detailed Explanation:
• General Combining Ability (GCA): This is the average performance of a parent in a series of crosses. It is associated with additive genetic effects, which are highly inheritable. GCA is traditionally estimated using half-sib families (progenies where only one parent is known/controlled, like in open-pollinated seed orchards). Therefore, Statement II is incorrect as it links GCA to full-sibs.
• Specific Combining Ability (SCA): This refers to cases where certain hybrid combinations perform better or worse than expected based on the average of the two parents (GCA). It is associated with non-additive genetic effects (dominance and epistasis). SCA is estimated using full-sib families (where both parents are known and controlled). Therefore, Statement I is incorrect as it links SCA to half-sibs.
• Conclusion: The two statements have effectively swapped the definitions/methods of measurement for GCA and SCA.
Step 2: Final Answer:
Both Statement I and Statement II are incorrect because GCA is estimated via half-sibs and SCA via full-sibs.
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