ARS Mains Examination Previous Year Question Paper GPB 1999

1. Write briefly :
   (a) Factors which promote vulnerability of crop varieties to diseases.
   (b) Components of horizontal resistance.
   (c) Mechanism of action of multiline cultivars.
   (d) Gene-for-gene hypothesis and second-gene-for gene-hypothesis.
   (e) Common phenolics and phytoalexins.
2. Distinguish between :
   (a) Linkage and pleiotropy.
   (b) Antibiosis and tolerance.
   (c) Correlation and regression.
   (d) Disease avoidance and escape.
   (e) Inbreeding coefficient and inbreeding depression.
   (f) Selection differential and selection advance.
   (g) Self-incompatability and male sterility.
   (h) Horizontal and vertical resistance.
   (i) Epistasis and overdominance.
   (j) General and specific combining ability.
3. Give major contributions of the following scientists :
   (a) W.I. Johanssen
   (b) N.I. Vavilov
   (c) G.H. Shull
   (d) B.P. Pal
   (e) M.S. Swaminathan
   (f) Ralph Riley
   (g) N.G.P. Rao
   (h) D.S. Athwal
   (i) K.W. Finlay
   (j) R.E. Comstock
4. How the following techniques can be used in genetic improvement ? Describe the methodology with appropriate examples :
   (a) Disruptive selection.
   (b) Metroglyph analysis.
   (c) Diallel selective mating system.
   (d) Monosomic analysis.
   (e) Reciprocal recurrent selection.
5. (a) Describe the different mechanisms of insect resistance.
   (b) What are transgenic plants ? How these are developed ? Describe the possible role of such plants in crop improvement.
6. (a) What are molecular markers ? Explain briefly their role in plant breeding ?
   (b) What are the important criteria that determine the success of gene transfer through plant genetic engineering techniques ?
7. (a) Discuss the steps involved in the development of hybrid rice.
   (b) Describe the present status of hybrid variety development in pigeonpea.
   (c) Write a brief note on the possibility of developing hybrid variety in wheat ?
8. (a) What is abiotic stress ? How will you proceed to screen germplasm for stress tolerance ? Discuss the screening system of major abiotic stresses in rice.
   (b) Describe the role of wild/alien species in breeding for tolerance to abiotic stresses.
9. (a) Grain legumes are generally cultivated as an inter crop with cereals. What are the criteria for selection of suitable plant types for such a system ?
   (b) How do you proceed to develop a stable variety of pulse crop of both inter-cropping and monoculture.
10. (a) What is clonal selection ? Describe various steps involved in the development of superior clones in sugarcane.
    (b) Define heterosis and explain the genetic basis of heterosis.