Agriculture 2024 Paper II 50 marks Discuss

Q4

(a) Give an account of cytoplasmic genetic male sterility and its utilization in plant breeding. Also discuss its limitations. (20 marks) (b) What is distant hybridization? Discuss its applications, achievements and limitations in plant breeding. (20 marks) (c) Discuss the guidelines for planning and organization of seed production programme. (10 marks)

हिंदी में प्रश्न पढ़ें

(a) कोशिकाद्रव्यी आनुवंशिक नर बाँझपन और इसकी पादप प्रजनन में उपयोगिता की चर्चा कीजिए। इसकी सीमाओं का भी वर्णन कीजिए। (20 अंक) (b) दूर संकरण क्या होता है? पादप प्रजनन में इसके अनुप्रयोगों, उपलब्धियों और सीमाओं का वर्णन कीजिए। (20 अंक) (c) बीज उत्पादन कार्यक्रम की योजना एवं आयोजन के लिए दिशानिर्देशों की विवेचना कीजिए। (10 अंक)

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Directive word: Discuss

This question asks you to discuss. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.

See our UPSC directive words guide for a full breakdown of how to respond to each command word.

How this answer will be evaluated

Approach

The directive 'discuss' demands a comprehensive, analytical treatment with balanced coverage across all three sub-parts. Allocate approximately 40% of time/words to part (a) on cytoplasmic male sterility (20 marks), 40% to part (b) on distant hybridization (20 marks), and 20% to part (c) on seed production planning (10 marks). Structure with a brief integrated introduction, detailed separate sections for each sub-part with clear sub-headings, and a concluding synthesis on how these techniques advance Indian food security.

Key points expected

  • Part (a): Explanation of CMS mechanism (S-cytoplasm vs N-cytoplasm), three-line system (A, B, R lines), and its exploitation in hybrid seed production; limitations including genetic vulnerability (T-cytoplasm in US maize 1970 epidemic), restorer gene dependency, and temperature sensitivity
  • Part (a): Specific Indian applications — CMS-based hybrids in rice (IR58025A, Pusa 6A), sorghum (CSH series), pearl millet (HB series), and mustard (DMH-11 controversy)
  • Part (b): Definition of distant hybridization (inter-specific and inter-generic crosses), techniques to overcome barriers — embryo rescue, bridge species, chromosome doubling; achievements like triticale, synthetic brassicas, and introgression of wild species genes
  • Part (b): Indian achievements — cotton (Gossypium hirsutum × G. barbadense), rice (Oryza nivara for grassy stunt resistance), and limitations including hybrid sterility, linkage drag, and long breeding cycles
  • Part (c): Seed production planning guidelines — isolation distances, field standards, seed certification stages (breeder → foundation → certified), roguing stages, and organizational aspects under Seed Act 1966 and New Seed Policy 1988

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Precise scientific terminology throughout: correctly distinguishes CMS from GMS, explains mitochondrial chimeric genes (urf13 in T-cytoplasm maize), accurately defines distant hybridization scope, and correctly identifies seed classes and certification standards under Indian regulationsGenerally correct concepts but confused terminology (e.g., conflates CMS with GMS, vague on hybridization barriers, generic seed production steps without certification hierarchy)Fundamental errors: describes CMS as nuclear gene effect, misidentifies distant hybridization as mere open pollination, or confuses breeder seed with certified seed classes
Quantitative reasoning15%7.5Specific numerical data: isolation distances for rice (3m for certified, 5m for foundation), seed multiplication ratios (1:100 to 1:200 for hybrids), germination standards (80% for certified), or genetic ratios in restoration (explains 3:1 or 1:1 segregation patterns)Mentions 'adequate isolation' or 'high multiplication ratio' without figures, or gives approximate ranges without precisionNo quantitative dimension, or completely incorrect figures (e.g., isolation in meters confused with kilometers, impossible seed ratios)
Indian context examples25%12.5Rich, specific Indian evidence: for (a) cites A2 cytoplasm in sorghum, Pusa 6A in rice, DMH-11 mustard; for (b) mentions Triticale var. 'DWR-1', cotton hybridization at CICR, wild rice introgression; for (c) references NSC, SFCI, state seed corporations, and Seed Act amendmentsGeneric mention of 'Indian hybrids' or 'ICAR research' without specific varieties, institutions, or policy referencesOnly foreign examples (US maize, wheat-rye in Mexico) with no Indian context, or irrelevant examples from horticulture/animal breeding
Diagram / process20%10Clear, labeled diagrams: three-line system schematic for CMS with A, B, R line relationships; distant hybridization process flow showing barriers and solutions; seed production chain diagram with quality control checkpoints; or well-structured tables comparing CMS typesMentions diagrams but describes them textually, or provides poorly labeled sketches that don't clearly illustrate relationshipsNo visual representation where clearly needed (especially for three-line system), or diagrams that misrepresent the biological relationships
Policy / extension angle15%7.5Integrates policy relevance: discusses GM mustard DMH-11 regulatory controversy for (a); biosafety concerns in transgenic distant hybrids for (b); links seed production to Seed Bill 2004 provisions, PPV&FR Act 2001, and PM-KISAN seed component for (c)Brief mention of 'seed quality important for farmers' or 'hybrid seeds need regulation' without specific policy instrumentsNo policy or extension dimension, or irrelevant discussion of general agricultural policy without seed-specific linkage

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