Q.74 Match List I with List II
| LIST I | LIST II |
|---|---|
| A. Damping off of seedlings B. Downy mildew of peas C. Loose smut of wheat D. Stem gall of coriander |
I. Ustilago nuda II. Pythium sp. III. Protomyces macrosporous IV. Peronospora pisi |
Choose the correct answer from the options given below:
(B) A-II, B-III, C-I, D-IV
(C) A-II, B-IV, C-III, D-I
(D) A-I, B-II, C-III, D-IV
The correct answer is option (A): A-II, B-IV, C-I, D-III.
Disease-Pathogen Matches
Damping off of seedlings is caused by Pythium species, a fungus-like oomycete that leads to seedling collapse in damp conditions. Downy mildew of peas is induced by Peronospora pisi, producing yellow patches and gray mold on leaves and stems. Loose smut of wheat results from Ustilago nuda (or Ustilago nuda tritici), where infected heads replace grains with black spore masses. Stem gall of coriander is due to Protomyces macrosporus, forming tumor-like galls on stems and fruits.
Option Analysis
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Option (A): A-II (Pythium), B-IV (Peronospora pisi), C-I (Ustilago nuda), D-III (Protomyces macrosporus). Matches all correctly.
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Option (B): A-II (correct), B-III (wrong; III is Protomyces), C-I (correct), D-IV (wrong; IV is Peronospora).
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Option (C): A-II (correct), B-IV (correct), C-III (wrong; III is Protomyces), D-I (wrong; I is Ustilago).
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Option (D): A-I (wrong; I is Ustilago), B-II (wrong; II is Pythium), C-III (wrong), D-IV (wrong).
Damping off of seedlings, downy mildew of peas, loose smut of wheat, and stem gall of coriander are key plant diseases in agriculture exams like those for life sciences students. This article solves the matching question (Q.74) with correct pathogens and detailed explanations.
Pathogen Identification
These diseases are caused by specific fungi or oomycetes, often seed-borne or soil-transmitted.
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Damping off of seedlings: Pythium sp. attacks germinating seeds in wet soils, causing rot and collapse.
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Downy mildew of peas: Peronospora pisi forms oospores in debris, leading to yellowing and mold under cool, moist conditions.
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Loose smut of wheat: Ustilago nuda infects embryos via seed, replacing heads with spores at flowering.
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Stem gall of coriander: Protomyces macrosporus produces chlamydospores in galls, favored by cold winters.
Correct Matching (Option A)
A-II (Pythium sp.), B-IV (Peronospora pisi), C-I (Ustilago nuda), D-III (Protomyces macrosporus).
Why Other Options Fail
Option B swaps B and D; III is stem gall, not peas. Option C mismatches C and D; loose smut is Ustilago. Option D incorrectly assigns A-I and B-II.
