Answer the following in about 150 words each : 10×5=50

(a) Mention the role of embryo rescue in interspecific hybridization.

(b) Explain 'cybridization'. Write one example of economically useful cybrid. Describe the methods to produce cybrids. 6+1+

Question

Answer the following in about 150 words each : 10×5=50

(a) Mention the role of embryo rescue in interspecific hybridization.

(b) Explain 'cybridization'. Write one example of economically useful cybrid. Describe the methods to produce cybrids. 6+1+3=10

(c) Write an account of plants used as natural dyes. Give binomial name and family of any three dye-yielding plants that are used as food additives. 7+3=10

(d) Distinguish between anther culture and microspore culture. Which technique is more advantageous? Give reasons. 8+2=10

(e) Write a note on the role of palynology in plant systematics.

UPSC Answer Check · Accepted Answer

This multi-part question requires explaining technical biotechnological concepts across five sub-parts. Allocate approximately 30 words each for (a), (c), and (e) (5 marks each), and 40 words each for (b) and (d) (10 marks each). Structure each sub-part as: definition → mechanism/process → specific example/application. For (b) and (d), prioritize comparative clarity and methodical sequencing. Use standard botanical nomenclature and cite Indian research contexts where relevant.
- (a) Embryo rescue: overcoming post-zygotic barriers in wide crosses, preventing embryo abortion, use in incompatible species like Lycopersicon esculentum × Solanum lycopersicoides
- (b) Cybridization: definition as cytoplasmic hybridization, transfer of cytoplasmic traits (CMS), example of Nicotiana tabacum cybrid with CMS for hybrid seed production, methods: PEG fusion, electrofusion, microinjection
- (c) Natural dyes: indigo (Indigofera tinctoria), saffron (Crocus sativus), turmeric (Curcuma longa) as food additives with binomials and families (Fabaceae, Iridaceae, Zingiberaceae)
- (d) Anther vs microspore culture: anther culture uses whole anthers with potential diploid callus from somatic tissue, microspore culture uses isolated haploid microspores; microspore culture more advantageous due to pure haploid origin, no diploid contamination, direct embryogenesis
- (e) Palynology in systematics: pollen morphology as taxonomic marker, exine ornamentation patterns, phylogenetic reconstruction, chemotaxonomic value of sporopollenin, aeropalynology for fossil calibration

Dimension	Weight	Max marks	Excellent	Average	Poor
Concept correctness	25%	12.5	Precise definitions for embryo rescue, cybridization, palynology; accurate distinction between anther and microspore culture including ploidy outcomes; correct understanding of cytoplasmic inheritance vs nuclear hybridization	Generally correct definitions with minor inaccuracies in technical details; conflates anther and microspore culture mechanisms or misses haploid/diploid distinction	Fundamental misconceptions such as treating cybridization as somatic hybridization, confusing embryo rescue with ovule culture, or misidentifying palynology as only fossil study
Diagram / labelling	10%	5	Clear schematic of protoplast fusion for cybridization or microspore isolation protocol; proper labelling of CMS transfer or anther structure vs isolated microspores	Basic diagram attempted with partial labelling; or mentions need for diagram without drawing	No diagram where essential (cybridization methods, culture comparison); or incorrect schematic showing nuclear transfer in cybridization
Examples & nomenclature	20%	10	Correct binomials with authorities implied: Indigofera tinctoria L. (Fabaceae), Crocus sativus L. (Iridaceae), Curcuma longa L. (Zingiberaceae); specific cybrid example like Nicotiana CMS system; Indian context for saffron/turmeric	Correct genera with minor species errors; families approximately correct; generic cybrid example without species specificity	Wrong binomials (e.g., Curcuma domestica instead of C. longa), incorrect families (e.g., Crocus in Liliaceae), or missing examples entirely
Process explanation	25%	12.5	Stepwise embryo rescue protocol (ovule excision, in vitro culture, embryo germination); detailed PEG/electrofusion methods for cybridization; logical comparison showing microspore culture eliminates diploid contamination via direct embryogenesis	General process description without sequential clarity; mentions methods without explaining mechanism; superficial comparison of culture techniques	No methodological detail; confuses processes (e.g., describes somatic hybridization for cybridization); incorrect sequence in embryo rescue
Application / ecology	20%	10	Links embryo rescue to crop improvement (tomato wild relative introgression); cybrid application to hybrid seed production and male sterility; palynology to resolving taxonomic controversies and reconstructing vegetation history; food safety aspect of natural dyes	Mentions applications generically without specific crop or research context; limited ecological significance for palynology	No practical applications cited; or incorrect applications (e.g., cybrids for disease resistance via nuclear genes); ignores agricultural/forensic value of palynology

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