Question:
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Gametophytic self incompatibility was first described by Hughes and Babcock in Crepis foetida.
Reason R: In gametophytic system, incompatibility reaction of pollen is determined by its own genotype and not by the genotype of the plant on which it is produced.
In light of the above statements, choose the most appropriate answer from the options given below:
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Gametophytic self incompatibility was first described by Hughes and Babcock in Crepis foetida.
Reason R: In gametophytic system, incompatibility reaction of pollen is determined by its own genotype and not by the genotype of the plant on which it is produced.
In light of the above statements, choose the most appropriate answer from the options given below:
Assertion A: Gametophytic self incompatibility was first described by Hughes and Babcock in Crepis foetida.
Reason R: In gametophytic system, incompatibility reaction of pollen is determined by its own genotype and not by the genotype of the plant on which it is produced.
In light of the above statements, choose the most appropriate answer from the options given below:
Show Hint
Gametophytic SI = Pollen's own genotype.
Sporophytic SI = Parent plant's genotype.
GSI is usually associated with wet stigmas, while SSI is associated with dry stigmas.
Sporophytic SI = Parent plant's genotype.
GSI is usually associated with wet stigmas, while SSI is associated with dry stigmas.
Updated On: Aug 13, 2026
- Both A and R are correct and R is the correct explanation of A
- Both A and R are correct but R is NOT the correct explanation of A
- A is correct but R is not correct
- A is not correct but R is correct
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: Understanding the Concept:
Self-incompatibility (SI) is a genetic mechanism that prevents self-fertilization in plants. There are two main types: Sporophytic (SSI) and Gametophytic (GSI).
Step 2: Detailed Explanation:
Assertion A Analysis: This is a historical fact in plant genetics. East and Mangelsdorf (1925) first described GSI in Nicotiana, but the specific details regarding Crepis foetida were indeed pioneered by Hughes and Babcock in 1950. Their work helped define the inheritance and mechanics of the gametophytic system.
Reason R Analysis: This is the fundamental definition of the Gametophytic system. In GSI, the incompatibility phenotype of the pollen is determined by its own haploid genotype (the S-allele it carries). For example, if a plant is \(S_1S_2\), it produces pollen grains that are either \(S_1\) or \(S_2\). If a pollen grain (\(S_1\)) lands on a stigma that also carries an \(S_1\) allele, it will be inhibited. In contrast, in Sporophytic SI, the pollen behavior is determined by the diploid genotype of the parent plant.
Since R defines the mechanism that Hughes and Babcock discovered/described in GSI, it serves as a valid explanation for the nature of the system mentioned in Assertion A.
Step 3: Final Answer:
Both A and R are correct and R is the correct explanation of A.
Self-incompatibility (SI) is a genetic mechanism that prevents self-fertilization in plants. There are two main types: Sporophytic (SSI) and Gametophytic (GSI).
Step 2: Detailed Explanation:
Assertion A Analysis: This is a historical fact in plant genetics. East and Mangelsdorf (1925) first described GSI in Nicotiana, but the specific details regarding Crepis foetida were indeed pioneered by Hughes and Babcock in 1950. Their work helped define the inheritance and mechanics of the gametophytic system.
Reason R Analysis: This is the fundamental definition of the Gametophytic system. In GSI, the incompatibility phenotype of the pollen is determined by its own haploid genotype (the S-allele it carries). For example, if a plant is \(S_1S_2\), it produces pollen grains that are either \(S_1\) or \(S_2\). If a pollen grain (\(S_1\)) lands on a stigma that also carries an \(S_1\) allele, it will be inhibited. In contrast, in Sporophytic SI, the pollen behavior is determined by the diploid genotype of the parent plant.
Since R defines the mechanism that Hughes and Babcock discovered/described in GSI, it serves as a valid explanation for the nature of the system mentioned in Assertion A.
Step 3: Final Answer:
Both A and R are correct and R is the correct explanation of A.
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