Plant Virology

• Phases of Pathogenesis in Fungal Infections:
• Infection Chain: In agricultural pathology examination frameworks, the sequence of disease development following contact involves:

• Infection (B): Initiation of parasitic relationship.
• Penetration (A): Physical mechanical or enzymatic entry through cuticle/stomata.
• Invasion (D): Spread of mycelium into surrounding tissues.
• Colonization (C): Extensive internal establishment and exploitation of host cells.
  • Sequential Order: Sequence (B) $\rightarrow$ (A) $\rightarrow$ (D) $\rightarrow$ (C) represents the designated scoring sequence (Option 2).

• Distribution of Cyst Nematodes (Heterodera spp.) in India:
• Occurring in India:
• Heterodera zeae: Corn cyst nematode, widely distributed in maize growing belts of India (first described from India by Koshy et al., 1970).
• Heterodera avenae: Cereal cyst nematode, causing 'Molya disease' of wheat and barley in Rajasthan and Haryana.
• Heterodera mothi: Cyperus cyst nematode, described from Indian sedges.
• Heterodera cajani: Pigeonpea cyst nematode.
• Not Occurring in India: Heterodera glycines (Soybean cyst nematode), a destructive pest causing devastating yellow dwarf in the USA, Brazil, and China, is a quarantine pest not established in India.
• Conclusion: Heterodera glycines does not occur in India (Option 2).

Correct option: (2) Heterodera glycines

• Insect Cuticle and Animal Names:
• Pair-by-Pair Matching:
• Arthropodin $\rightarrow$ (II) Zone beneath the wax layer: Arthropodin is the water-soluble structural protein of the untanned procuticle, situated directly beneath the epicuticle.
• Cement layer $\rightarrow$ (I) Tectocuticle: The outermost lipid-protective layer of the epicuticle (secreted by dermal glands) is termed the cement layer or tectocuticle.
• Pavo cristatus $\rightarrow$ (IV) Peacock: Scientific name of the Indian national bird (Indian Peafowl).
• Sus scrofa $\rightarrow$ (III) Wild boar: Scientific name of the wild swine/boar, an agricultural mammalian pest.
• Correct Choice: Option 3 maps (A)-(II), (B)-(I), (C)-(IV), (D)-(III).

Correct option: (3) (A) - (II), (B) - (1), (C) - (V), (D) - (ttl)

• Reproductive Biology of Mulberry (Morus alba):
• Statement (I) is correct: Mulberry trees can be dioecious, monoecious, or polygamodioecious. Many commercial cultivated varieties are monoecious, bearing separate male and female catkins on the same plant.
• Statement (II) is correct: Sex expression in mulberry is influenced by environmental conditions; high temperatures, long photoperiods, and moisture stress promote staminate (male) flower induction and maleness.
• Conclusion: Both Statement (I) and Statement (II) are correct (Option 1).