Effect of terminal water stress on growth, plant water status and yield of pearl millet genotypes

Two landrace based population (Western Rajasthan and Barmer Populations), three composites derived from non-land races (Pusa-266, ICTP-8203 and HHVBC) and one variety CZP-9802 of pearl millet (Pennisetum glaucum (L.) R. Br.) were subjected to water stress at the reproductive growth stage (50 days after sowing) by withholding irrigation till permanent wilting point in a pot trial. Water deprivation decreased plant water potential and relative water content (RWC) that led to a significant decline in the rate of net photosynthesis (PN), chlorophyll content, stomatal conductance, chlorophyll fluorescence parameters (Fv/Fm and Fm), nitrate reductase (NR) activity and grain yield. Among various genotypes, Pusa-266 and CZP-9802 showed lower reduction in RWC, PN, chlorophyll content, Fv/Fm ratio, NR activity and yield under water stress as compared with genotypes ICTP-8203, Barmer Population and Western Rajasthan Population. Thus, a combination of above physiological parameters, which had high correlation with yield as well as moderate to high heritability, can effectively be used to screen genotypes with higher tolerance to terminal drought in pearl millet