Question

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Barbery is an alternate host for Puccinia graminis f. sp. tritici.
Reason R: Barbery play key role in rust epidemics in India.
In light of the above statements, choose the correct answer from the options given below

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Hint:

Remember: In India, wheat rust is effectively microcyclic or persists via Uredospore oversummering.
K.C. Mehta's findings are a cornerstone of Indian plant pathology history.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question examines the life cycle and epidemiology of wheat stem rust (Puccinia graminis tritici) specifically in the context of the Indian subcontinent.
This requires distinguishing between the biological potential of a host and its actual ecological significance in a specific geographical region.

Step 2: Detailed Explanation:

• Analysis of Assertion A: Puccinia graminis tritici is a heteroecious rust fungus, meaning it requires two unrelated hosts to complete its full life cycle.
The primary host is wheat (Triticum aestivum), where the uredial and telial stages occur.
The alternate host is the Common Barberry (Berberis vulgaris), where the pycnial and aecial stages occur following the sexual recombination process.
Biologically, Barberry is indeed the alternate host for this fungus. Thus, Assertion A is True.

• Analysis of Reason R: In India, the epidemiology of wheat rust was extensively studied by Dr. K.C. Mehta.
He discovered that in the Indian plains, the inoculum for seasonal epidemics does not come from the Barberry bushes found in the high altitudes of the Himalayas.
The environmental conditions and the lack of synchronization between the aeciospore release on Barberry and the wheat season in the plains render the Barberry's role in the Indian rust cycle negligible.
Instead, the rust survives year-round as uredospores on self-sown wheat or off-season crops in the southern hills (Nilgiri and Palni hills) and the Himalayan foothills, from where they are blown by wind to the plains.
Therefore, Barberry does not play a key role in rust epidemics in India. Thus, Reason R is False.
Final Answer:
Assertion A is a correct biological statement about the host range, but Reason R is factually incorrect regarding Indian agricultural epidemiology.
The correct option is (C).