Evaluation of germplasm and advanced breeding lines of rabi sorghum [Sorghum bicolour (L.) Moench] for post flowering drought tolerance.

Abstract

Forty two genotypes were tested together during rabi season 2015-16 under three water regimes 1. Well watered -irrigated throughout the crop season, 2. Water stressed ie irrigation till 45 days after sowing and 3. Water stressed ie. irrigation till 30 DAS along with four checks viz., M35-1, Phule Anuradha, CSV 22, and CSV 26. The design of experiment was split plot design with three replications. Drought tolerance and susceptible genotypes were categorised on the basis of stress susceptible index (SSI), Weighted Mean Index (WMI) and regression line. Based on these criteria genotypes Phule Anuradha x Sangola Hondi, Sangola hondi x BRJ 62, SLR 24 x BRJ 62, IC 392155, CRS 7, CRS 20, CRS 48, Selection 3 and IC - 343586 were categorised as drought tolerant. Correlations between peduncle length (cm) and days to flowering were negative and significant under all environments (-0.36* *,-0.44* * and -0.39* *) indicating higher peduncle length earlier the flowering. Under less soil moisture condition early flowering and maturity traits is important as it helps in completing life cycle with available soil moisture, thereby imparting drought tolerance. Correlations between grain yield and per cent panicle emergence were positive and significant (0.67* *, 0.44* * and 0.37* *) under all environments. Correlation between per cent reduction in grain yield and per cent reduction in leaf area at the time of flowering under one irrigation was (r=0.53*) significant and positive. Traits like early flowering, long peduncle length and less reduction in leaf area at the time of flowering were found to be associated with drought.