Standardized partial regression coefficients of root length density (RLD) measured at different days after sowing (DAS) on grain yield at maturity of 12 diverse genotypes of chickpea both under (A) drought stress and (B) optimal irrigation in a Vertisol during 2009–10 post-rainy season. The different number of asterisks on top of the bars denotes the different level of significant correlation between RLD and grain yield (*P < 0.05, **P < 0.01, ***P < 0.001). a = 0–15, b = 15–30, c = 30–45, d = 45–60, e = 60–75, f = 75–90, g = 90–105 and h = 105–120 cm soil depth.