Master’s Degree Programme: Genetics and Plant Breeding Written Qualifying Examination – I Semester (2014–15) (GKVK)

University of Agricultural Sciences, GKVK, Bengaluru – 560 065

Department of Genetics and Plant Breeding

Master’s Degree Programme: Genetics and Plant Breeding
Written Qualifying Examination – I Semester (2014–15)
Duration: 3½ Hours  Maximum Marks: 100

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I. Answer the following (Any 10)

(1 × 10 = 10 marks)

1. Monosomics

2. Aneuploidy

3. Define breeding value in terms of average effects of genes.

4. Define average effect of a gene.

5. Types of heterosis.

6. Role of recurrent selection.

7. Backcross breeding for recessive traits.

8. Development of RILs.

9. Define gene action.

10. Explain the biochemical basis of heterosis.

11. Marker-assisted selection (MAS).

12. Cytoplasmic male sterility (CMS).

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II. Substantiate the following (Any 10)

(2 × 10 = 20 marks)

1. Selection in M₁ is not feasible.

2. Selection in pure lines is not effective.

3. Prebreeding is important in crop breeding programmes.

4. Epistatic variance is not fixable.

5. Heterosis is heritable.

6. Key features of meiosis that contribute to genetic variation.

7. Cross over helps in creation of variability.

8. Marker-assisted backcross breeding is more useful in transfer of recessive genes.

9. Inheritance of X-linked traits provides evidence of physical basis of heredity.

10. Explain with diagram the molecular basis of heterosis.

11. Self incompatibility and its significance in crop improvement.

12. Selection in F₁ population is not possible in all environments.

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III. Write short notes on the following (Any 10)

(3 × 10 = 30 marks)

1. Cytoplasmic and nuclear inheritance.

2. Gene action.

3. Reciprocal recurrent selection.

4. Development of RILs.

5. Recurrent selection method of breeding.

6. Polyploidy and aneuploidy in crop improvement (with examples).

7. Self incompatibility and its types.

8. Role of heterosis in plant breeding.

9. Describe Mather’s method of diallel analysis.

10. Describe Mahalanobis D² analysis.

11. Limitations of mutations.

12. Inversions and their significance.

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IV. Answer the following (Any 8)

(5 × 8 = 40 marks)

1. Write on the different objects used for irradiation along with their merits and demerits.

2. Discuss the various effects of alkylating agents on DNA.

3. What are the important steps involved in the development of hybrids? How are the newly developed inbreds evaluated for high combining ability and high yield?

4. Taking an example of ABCDEFGH on a pair of chromosomes, if paracentric inversion occurs between D and E genes, draw and show gametes formed after meiosis. What is the genetic significance?

5. What is Marker-Assisted Selection? Write its principles.

6. Explain cytological evidence to demonstrate that the F₁ plant heterozygous for two pairs of alleles will produce four types of gametes in equal frequencies.

7. Explain the experiment carried out by Creighton and McClintock to explain the cytological basis of crossing over.

8. Explain benefits of quantitative traits based on graphical analysis of diallel mating design.

9. Derive components of means of P₁, P₂, F₁, F₂, B₁ and B₂ generations assuming adequacy of the additive-dominance model.

10. Explain how inheritance of leaf variegation is different from inheritance of traits governed by nuclear genes.

11. What is male sterility? Explain the ABR line system of hybridization.

12. Write the principle and purpose of selection. Explain different types and patterns of response to selection for various traits.

13. Explain briefly about development of synthetics and composites.