Assessment of grain quality traits in rice under normal and water deficit condition

Abstract

The main objective of this study was to assess the combining ability for rice grain quality to recognize the most desirable genotypes for rice breeding programs. A half diallel cross was made among eight rice genotypes. The obtained 28 F1 and their parents were evaluated in two separate irrigation experiments; the first experiment was irrigated every four days (normal condition). The second experiment was irrigated every ten days (a stress condition). The two experiments were designed in randomized complete block design with three replications. The results indicated that water deficit treatment significantly reduced all the studied traits except for amylose content % was increased under stressed treatments. General combining ability mean squares were highly significant for all the studied features except gelatinization temperature under drought irrigation. Specific combining ability mean squares were highly significant for grain elongation % under both conditions and amylose content % under water deficit; this indicates the importance of additive and non-additive genetic effects in the inheritance of these traits. Two crosses, Sakha106 × Sakha107 and Sakha106 × Sakha108 had the highest desirable mean values for hulling (%), milling (%), head rice, and gelatinization temperature, also lowest amylose content under both conditions. Three crosses, Giza 179 X Sakha 107, Giza 179 X Sakha 108, and Sakha 106 X Sakha 108, had the highest mean values of grain elongation % under both conditions. The cross Sakha107 × sakha108 showed highly significant positive desirable SCA effects for hulling (%) milling (%) gelatinization temperature and grain elongation. The varieties Sakha 107 and Sakha108 were the best general combiners and could be used in breeding programs for improving all the studied traits under both conditions.