I. Answer any three of the following in about 200 words each: 20 x 3 60


What do you mean by independent assortment of genes? Diustrate with an example that linked genes cannot assort independently. Diagrammatically represent the coupling and repulsion phase of linkage. What will be the parental and recombinant gametes produced by an individual in repulsion phase?


Write notes on any four:


Trisomics Vs triploids


DNA Vs RNA


Spontaneous Vs induced mutation

Mendelian inheritance Vs cytoplasmic inheritance


Sex chromosome Vs autosomes.




Describe the various structural chromosome aberrations with the help of suitable diagrams. Draw the pachytene configurations when these aberrations are in heterozygous condition.


Define euploidy. Describe the cytological and morphological features of allopolyploids, the mode of their experimental induction and role in evolution and crop improvement.


2. Differentiate between the following: 20x3=60

Qualitative and quantitative traits


Mass selection and pureline selection


Pedigree and bulk method
Primary and secondary centres of origin of crops

List the various sources of disease resistance. Describe the backcross method of breeding if the disease resistance is governed by a dominant gene.


How the genetic engineering and plant tissue culture supplement classical plant breeding?