Genetic variability and relative drought tolerance in interspecific progenies of Brassica juncea

Abstract

Genetic variability plays an important role in plant breeding because hybrids between lines of diverse origin generally display a greater heterosis than those between closely related parents. Segregating progenies of interspecific crosses PCR-7/BPKR-13, RH-819/MCP-03, RH819/BPKR-13 and Varuna/BPKR-13 were maintained till F7 generation through selfing. The relative drought tolerance of each progeny was quantified with respect to seed yield through Drought Susceptibility Index (DSI). The progenies were reported fertile at every generation (F1 to F6) and fertility ranged from 85% to 98%. The overall mean performance of progenies was comparatively higher in irrigated environment for days to 50% flowering, days to maturity, fruiting zone length, main shoot length, siliquae on main shoot, siliquae per plant, 1000 seed weight, seed yield per plant and protein content. Drought Susceptibility Index (DSI) was calculated for each genotype as a criterion of drought tolerance. The lowest value indicates the highest level of drought tolerance and vice-versa. The values of DSI ranged from -0.139 (07-547) to 1.316 (07827) (Table-2). The genotypes 07-547, 07-515 and 07-510 had lower DSI values (< or ~0.00), thus rated as drought tolerant. The progenies could be distinguished from each other by means of a combination of fragments which is repeatedly present in one progeny and absent in the other. However, out of 472 scored band, about 83 % were polymorphic.