IDENTIFICATION OF TERMINAL MOISTURE STRESS TOLERANT DOLICHOS BEAN (Lablab purpureus L. Sweet, var. lignosus) BACKCROSS INBRED LINES (BILS)
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Date
2021-12-28
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University of Agricultural Sciences, Bangalore
Abstract
Predominantly rain-fed crops like dolichos bean frequently experience terminal moisture stress (TMS) resulting in huge grain yield losses. Development and deployment of TMS tolerant cultivars will help stabilize dolichos bean production under TMS nvironments. Based on empirical studies across crop groups, we hypothesized that segregating populations/advanced breeding lines derived from crosses involving landraces/locally adapted genotypes are putative candidates for selecting TMS tolerant ones in dolichos been. To test this hypothesis, eight selected backcross inbred lines (BILs) derived from cross between high-yielding, determinate, photoperiod-insensitive variety and high yielding, indeterminate, photoperiod-sensitive landrace were field-evaluated for grain yield under two managed moisture regimes, namely (1) non-stress (NS) and (ii) TMS environments at two locations, viz, Gandhi Krishi Vignana Kendra (GKVK), Bangalore, India and Agricultural Research Station (ARS), Ballary, India. Reported four drought
tolerance indices, namely Arithmetic Mean Productivity (AMP), Geometric Mean Productivity (GMP), Harmonic Mean Productivity (HMP) and Stress Tolerance Index (STI) were used to detect and quantify variability among BILs and to identify those with
tolerance to TMS environment. Grain yield of BILs reduced up to 50 % due to TMS. Based on the criteria of (1) better ability to discriminate BILs for responses to TMS environment and (ii) high magnitude of correlation of indices with grain yield under NS and TMS environments, STI and GMP were found desirable. Based on the combination of STI and GMP, three BILs (BILs 08, 10 & 26) were identified as TMS tolerant ones with high grain yielding potential under both NS and TMS environments.