Agriculture 2024 Paper II 50 marks Discuss

Q2

(a) What is chromosomal aberration? Briefly discuss the changes in chromosomal structure due to aberrations. (20 marks) (b) Discuss the importance of crop genetic resource conservation and utilization. (20 marks) (c) Briefly explain the Soil-Plant-Atmosphere Continuum (SPAC). How are rooting characteristics related to the moisture extraction pattern from the soil? (10 marks)

हिंदी में प्रश्न पढ़ें

(a) गुणसूत्री विपथन (एबरेशन) क्या होता है? विपथनों के कारण गुणसूत्र की संरचना में होने वाले परिवर्तनों का संक्षेप में वर्णन कीजिए। (20 अंक) (b) फसल आनुवंशिक संसाधन के संरक्षण और उपयोगिता के महत्व की चर्चा कीजिए। (20 अंक) (c) मृदा-पौधा-वायुमण्डल सातत्य (एस० पी० ए सी०) की संक्षेप में व्याख्या कीजिए। मृदा से नमी निष्कर्षण का स्वरूप जड़ों की विशेषताओं से कैसे संबंधित है? (10 अंक)

Evaluate your answer to this question → See all 2024 Agriculture questions

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' for part (b) and 'explain' for parts (a) and (c) demand comprehensive coverage with analytical depth. Allocate approximately 40% word/time to part (a) on chromosomal aberrations, 40% to part (b) on genetic resource conservation, and 20% to part (c) on SPAC. Structure with a brief integrated introduction, dedicated sections for each sub-part with clear sub-headings, and a conclusion linking genetic diversity conservation to climate resilience.

Key points expected

  • Part (a): Define chromosomal aberration as structural/ numerical changes; explain structural changes—deletion, duplication, inversion, translocation—with specific examples like Cri-du-chat syndrome or BCR-ABL translocation in crops
  • Part (a): Distinguish between intrachromosomal (within same chromosome) and interchromosomal (between non-homologous chromosomes) aberrations; mention mutagenic agents causing such changes
  • Part (b): Elaborate on importance of crop genetic resource conservation—insurance against genetic erosion, source for resistance genes (e.g., IRRI's search for rice blast resistance), meeting future breeding needs for climate adaptation
  • Part (b): Discuss utilization through core collections, pre-breeding, and participatory plant breeding; cite Indian examples like NBPGR's national gene bank at New Delhi and cryopreservation of citrus at NRCC, Nagpur
  • Part (c): Define SPAC as integrated system of soil-plant-atmosphere with water potential gradient as driving force; explain components—soil water potential, root water potential, leaf water potential, atmospheric water potential
  • Part (c): Explain rooting characteristics—rooting depth, density, distribution pattern—and their relation to moisture extraction; contrast shallow fibrous roots (rice) vs deep tap roots (cotton, pigeonpea) in Indian cropping systems

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness25%12.5Precise definitions for all three parts: correctly classifies structural aberrations (deletion, duplication, inversion, translocation) with ploidy implications for (a); accurately distinguishes in-situ, ex-situ, and in-vitro conservation methods for (b); correctly identifies water potential gradients and resistances in SPAC for (c)Broadly correct definitions with minor errors—may confuse Robertsonian translocation with reciprocal translocation, or conflate genetic diversity with agro-biodiversity without nuance; SPAC explanation misses resistance componentsFundamental conceptual errors—confuses chromosomal aberration with gene mutation, mistakes genetic resource conservation for seed production, or describes SPAC as merely soil-plant relationship ignoring atmospheric continuum
Quantitative reasoning15%7.5Includes quantitative aspects: mentions ploidy changes (haploid, diploid, polyploid), approximate gene bank holdings (NBPGR conserves ~4.5 lakh accessions), or water potential values in MPa for SPAC components; calculates extraction front velocity or root:shoot ratiosVague quantitative references—mentions 'large collections' or 'deep roots' without specific numbers; qualitative description of water movement without potential gradientsNo quantitative dimension; purely descriptive answer missing all numerical data, percentages, or measurement units relevant to genetic diversity indices or soil moisture depletion patterns
Indian context examples20%10Rich Indian specificity: for (a) cites induced aberrations in Indian crop improvement (e.g., Triticum sphaerococcum from EMS); for (b) details NBPGR network, cryopreservation at NBPGR, and success stories like 'Kufri Jyoti' potato from indigenous Solanum tuberosum; for (c) compares moisture extraction in rice-wheat vs cotton-wheat systems of Indo-Gangetic plainsGeneric mention of 'Indian gene banks' or 'local varieties' without specific institutions, programmes, or cultivar names; SPAC discussion lacks Indian soil/crop contextNo Indian examples; uses only international references (CIMMYT, IRRI) without connecting to Indian national programmes, or completely omits context-specific illustrations
Diagram / process20%10Clear, labelled diagrams: for (a) schematic showing structural aberration types with chromosome banding patterns; for (b) flowchart of conservation-utilization pipeline from collection to cultivar release; for (c) SPAC diagram with water potential gradient and resistances (soil, root, xylem, leaf boundary layer), plus root distribution profile showing moisture depletion zonesOne relevant diagram described but poorly labelled, or verbal description of diagrams without actual sketching; misses critical components like resistance pathways in SPACNo diagrams attempted; or diagrams completely wrong (e.g., showing mitosis instead of aberration types, confusing SPAC with nitrogen cycle); illegible sketches without labels
Policy / extension angle20%10Strong policy integration: for (b) discusses PPV&FR Act 2001, Nagoya Protocol, India's Biodiversity Act 2002, and Farmers' Rights; links genetic resources to Seed Village Programme and climate-smart agriculture; for (c) connects SPAC understanding to precision irrigation (PMKSY), deficit irrigation scheduling, and extension messages for water-stressed areasMentions 'government schemes' generically without specific policy instruments; weak link between technical content and farmer-level application or national food security goalsNo policy or extension dimension; purely academic treatment ignoring how genetic resource conservation translates to seed security, or how SPAC knowledge informs irrigation advisory services

Practice this exact question

Write your answer, then get a detailed evaluation from our AI trained on UPSC's answer-writing standards. Free first evaluation — no signup needed to start.

Evaluate my answer →

More from Agriculture 2024 Paper II