Performance of Promising Hybrid Rice Genotypes Under Different Irrigation Intervals

Abstract

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.

Genetic Diversity Among some of Rice Genotypes under Water Shortage

“…On the other hand, the highest value of number of unfilled grains panicle-1 produced by ARD6-8-1-1-1-1-5 under drought treatment , while the lowest value of number of unfilled grains panicle-1 produced by Nerica 7 and Egyptian Yasmin under Normal irrigation. These results are in harmony with those stated by Hashem et al (2016), Zaman et al (2018) and Gewaily et al (2021) who reported that water deficit induced several changes in the structure and functional processes of reproductive organs in the rice, resulting to fluctuations in fertilization or premature abortion of the seed. leaves senescence, shortens in grain filling period, reduction in photosynthesis and enhancing soluble sugars remobilization from grains to other vegetative organs are clear with water stress at the reproductive stage.…”

“…While, the lowest values of grain yield were obtained with Nerica 7 under water shortage with the highest percentage (33.63 %) of yield reduction compared to its production under normal irrigation . The results are inconformity with that stated by Kondhia et al (2015) and Gewaily et al (2021).…”

“…These data are similar to those reported by Gaballah (2009). The delay in heading of rice is common under drought conditions EL-Refaee et al (2005), Gewaily et al (2021) which is recommended that, the benefit in those environments exposed to water deficit. The delay in heading and maturity could be considered as good criteria in screening tests for tolerance to water shortage, because the effect of drought on the trait was consistent Mohamed et al (2019).…”