Genetic Studies of Pearl Millet (Pennisteum Glaucum L.) Under Water Stress at Different Growth Stages

Abstract

Fifteen pearl millet genotypes were tested under four levels of water treatments at two locations (ELRawakeeb 2003/04 and Shambat 2004/05), to estimate the genetic variability and heritability for drought tolerance in pearl millet and to determine the correlation between yield, its components and other traits as well as to identify the most yield stable genotype under drought stress condition. Split – plot design with three replications was used. Four levels of water stress were used in the main – plot, namely; normal irrigation every 7 days (W0), irrigation every 14 days during vegetative stage (W1), irrigation every 14 days during filling stage (W2) and irrigation every 14 days throughout the vegetative and grain filling stage (W3).The genotypes were used in sub plots. At all locations, significant differences among the evaluated genotypes were detected for all studied characters. The combined analysis revealed highly significant variation due to genotypes and genotypes x location interaction for most of the studied characters. A wide range of genetic variability was detected among genotypes for drought tolerance. Yield and yield components were significantly reduced by water stress. Whereas, the water stress during grain filling stage had small effect on yield and its components. Estimates of genotypic coefficient of variation exhibited narrow range while the estimates of heritability exhibited wide range of variation. Grain yield/ plant exhibited strong positive phenotypic and genotypic correlation with some yield components and it has negative correlation with days to 50 % flowering, date to maturity and dead part length. There was positive and significant correlation between grain yield under drought condition (Yd) and grain yield under normal condition (Yw). Whereas, the association between drought tolerance (Yd/Yw) with Yw was negative. The path analysis reflected that the fertile tillers per plant had highest positive direct effect on grain yield per plant, followed by number of seeds per head and 1000–seed weight. The genotypes exhibited significant variation for stability as measured by (regression coefficient (bi), deviation from regression line (S2đ). The genotypes Madelkawiyia, JM36, and JM38 showed high yield and high stability therefore, these genotypes could be recommended for improvement of pearl millet under drought conditions.