Yield and Water Relations of Pearl Millet Genotypes under Irrigated and Nonirrigated Conditions1

Abstract

AbstractDrought resistance in pearl millet [(Pennisetum americanum (L.) Leeke] makes it BIR important food crop in arid and semiarid regions, but research is limited on drought resistance and physiological responses to water stress. To study the relationship of pearl millet yield to physiological characteristics, 10 pearl millet genotypes were grown under irrigated and nonirrigated conditions on a silt loam soil (fine‐silty, mixed mesic, Pachic Haplustoll). Leaf diffusion resistance of adaxial (LDRad) and abaxial (LDRab) surfaces, leaf water potential (ΨL, leaf osmotic potential (ΨrL, and stem osmotic potential (Ψrs) of genotypes were recorded in both treatments in the afternoon (1200 to 1700 h) when the crop was water‐stressed. Leaf diffusion resistance (LDR) for a leaf was calculated as LDR = (LDRad × LDRab/(LDRad + LDRab). LDRad, LDRab, LDRab, LDR, ΨL, ΨrL, and Ψrs observed for each genotype were averaged over the stress period and correlated with yields and yield ratios (nonirrigated yield/irrigated yield) of genotypes. Majority of genotypes studies did not differ significantly (P<0.05) in average afternoon LDRab, ΨL, ΨrL, and Ψrs, and water use (WU) in both the treatments except that genotypic differences were significant in average afternoon LDRad and LDR in the nonirrigated treatment. Grain yield was significantly correlated with LDRab in both irrigated (r = −0.90) and nonurigated (r = −0.72) treatments, suggesting that high LDRab of genotypes is associated with low grain yield. Grain yield ratio was significantly correlated with LDRab (r = 0.71) and LDR (r = 0.66) in the irrigated treatment and with ΨrL (r = 0.64) and Ψrs (r = 0.78) in the nonirrigated treatment. Average afternoon ΨL did not correlate with grain yield or grain yield ratio. It is concluded that average afternoon LDRab could be used to rank pearl millet genotypes for their grain yield in both stressed and nonstressed environment.