PJB-2020-203
COMBINING ABILITY AND GENE ACTION FOR YIELD CHARACTERS OF NEW AROMATIC HYBRID RICE PARENTAL LINES UNDER WATER STRESS CONDITIONS
Hamdi Fetouh El-Mowafi
Abstract
Twenty hybrid rice combinations developed from five aromatic cytoplasmic male sterile (CMS) lines and four restorers, three of them aromatic were evaluated under both normal and water stress conditions. These combinations were investigated for agronomic and yield characters to assess estimation of combining ability and gene action and to identify the best female, male parents and best hybrid combinations. All characters in this study were significantly affected by water deficit condition. It was decreased by increasing the drought under water stress condition (irrigation every 12 days) comparing with normal irrigation condition. The reduction in each character caused by water stress condition differed genotype to another. The highest grain yield plant-1 was obtained of the hybrids, Pusa12A/IR25571-31R (42.6 g), IR58025A/PR2 (42.31 g), IR68902A/PR2 (40.47 g) and Pusa12A/Giza Basmati 201 (40.17 g) under water stress condition. The lowest reduction% was recorded for the maintainer Pusa11A/B (9.23%) and the hybrids, IR68902A/Giza Basmati 201 (16.37%) and IR68902A/PR2 (18.29%). The results revealed that the additive variance (σ2 A) and relative the importance of general combining ability (GCA) % for the characters, days to maturity, plant height, and 1000-grain weight under both normal and water stress conditions. The CMS line IR58025A/B was the best combiner for grain yield plant-1 under both normal and water stress conditions, respectively. The estimated values of variance due to specific combining ability (SCA) for plant height, spikelets panicle-1, panicles plant-1, panicle weight, filled grains panicle-1, spikelet fertility% and grain yield plant-1 under water stress conditions suggesting greater importance of non-additive variance. PR2 was the best combiner for plant height, panicles plant and grain yield plant-1 under water stress condition. Four combinations viz, Pusa11A/PR1, Pusa12A/IR25571-31R, Pusa12A/Giza Basmati 201 and Pusa13A/PR1 possessing significant and positive SCA effect for grain yield plant-1 under both normal and water stress conditions. Key words: Hybrid rice, aromatic rice, CMS, water stress, combining ability.
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