GENETIC POTENTIAL OF INTERSPECIFIC DERIVATIVES AS DONORS FOR RESISTANCE TO SOME BIOTIC AND ABIOTIC STRESSES IN GROUNDNUT (Arachis hypogaea L.)
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Date
1996
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UNIVERSITY OF AGRICULTURAL SCIENCES, DHARWAD
Abstract
"An investigation was carried out to assess the genetic potential of interspecific derivatives as donors for resistance to foliar diseases (early and late leafspots and rust), Spodoptera litura, Sclerotium rolfsii besides dormancyin groundnut. The experiment was conducted during kharif, 1995 at M.R.S., University of Agricultural Sciences, Dharwad. Nine cross combinations were obtained by taking Spanish cultivars viz., J 24, Dh 40 and KRG 1as ovule parents and crossed
with stress resistant moderatly dormant and high yielding interspecific derivatives viz., GBFDS 272, VG 101 and CS 16. The parents along with three dormant checks viz., Dh 8, DER and R 8972 were evaluated for various characters. The crosses were assessed for generating productive segregants with resistance to biotic and abiotic stress besides productivity in F2 derived F4 generation. The late maturing interspecific derivatives were significantly superior to ruling Spanish cultivars for dormancy and resistance to foliar diseases. Among them GBFDS 272 was also superior for resistance to damage due to Sclerotium rolfsii (DSL) and Spodoptera litura (DSP). But early maturing Spanish entries recorded high pod loss due to increased incidence of in situ germination and S. rolfsii. When phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were taken as indicators of variation, moderate to high level of variation was evident for DSL, DSP and dormancy while it was low for remaining green leaf area (RGLA), pod yield (PY), selling per cent (SP) and sound mature kernel per cent (SMK). Heritability was high for dormancy and moderate for biotic stresses. Genetic gain was maximum for dormancy followed by DSL and DSP but was low for RGLA, PY, SP and SMK. Significant differences were not evident in the mean performance of the crosses indicating futility of selection among crosses. Crosses as a whole were significantly potential for giving high frequency of desirable segregants for DSL and DSP but it was laow for RGLA. Only 38.8% of plants turncdout to be crcct-sequential and early maturing while frequency of significantly superior erect segregants for other characters were low. But proportion of such plants were comparable to that of whole population. Thus it would be possible to enhance the frequency of desirable erect segregants simply by increasing erect plants. Although frequency of segregants superior to JL 24 were relatively high in two parameter combinations but frequency of these lines was very low for combinations of more than two characters. Correlation and association analysis showed that different characters were not completely antagonistic to each other. Thus it would be possible to increase the frequency of desirable segregants through selective intermating.
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No. of references 185