Performance of promising hybrid rice genotypes under different irrigation intervals [electronic resource].

Includes references.

Water shortage stress is the most critical abiotic factor reducing rice yield. Water deficit stress at whichever of the rice critical growth stage causes decline in yield. A field experiment was conducted at the Experimental Farm of Sakha Agricultural Research Station, Kafrelsheikh, Egypt during 2018 and 2019 seasons, to investigate the effect of four irrigation intervals (continuous flooding(I1), irrigation every six days(I2), nine days(I3) and twelve days(I4)) on performance of five genotypes (Giza 178, IR 69625A/Giza 178, IR 70368A/Giza 178, IR 69625A/Giza 179 and IR 69625A/Giza 181). Strip plot design, with four replications was used. The horizontal plots were assigned to irrigation treatments, while the vertical plots were assigned to rice genotypes. Different drought tolerance indices such as abiotic tolerance index (ATI), stress susceptibility index (SSI), mean productivity (MP), tolerance index (TOL) and stress susceptibility percentage index (SSPI) were tested in screening superior rice genotypes. The results showed that days to 50% heading, plant height, panicle length, panicle weight, number of effective tillers hill-1, spikelet's number panicle-1, number of branches panicle-1, seed set (%), 1000-grain weight (g), number of filled grains panical-1, grain yield t ha-1, harvest index (%) and biomass weight t ha-1 were highly significantly affected by the interaction between irrigation intervals and genotypes. The highest values of grain yield were obtained by IR69625A/Giza 181 under continuous flooding irrigation during both seasons. Based on results of different drought tolerance indices, IR69625A/Giza 181 showed lowest values of ATI, SSI and TOL and the highest values of MP and SSPI and was identified as drought tolerant genotype.
Key words: Rice genotypes, irrigation intervals, drought tolerance indices and grain yield.

Summary in Arabic.