Evaluation of New Promising Rice Lines Under Water Deficit Conditions Based on Grain Yield, Quality and Stress Tolerance Indices تقييم سلالالات مبشرة من الأرز تحت ظروف نقص المياه على أساس محصول الحبوب وصفات الجودة و دلائل الإجهاد المائي

Abstract

Two field experiments were carried out at the Experimental Farm of Sakha Agricultural Research Station during 2019 and 2020 growing seasons, to evaluate 21 rice genotypes (18 new promising lines and three commercial check varieties) for grain yield, yield components and quality characters under normal and water deficit conditions. Moreover, eight stress tolerance indices were calculated based on grain yield under water deficit and normal conditions to differentiate the water deficit tolerant genotypes from sensitive ones. The results showed that the variances due to years, environments, genotypes and their interactions were significant for most studied traits. All mean values of the studied traits decreased under water deficit stress condition compared to those under normal condition. The earliest genotypes were L4, L15 and L12 under normal condition. Whereas under stress condition L11,Giza 179 and Sakha 107 were the earliest ones. The most desirable mean values towards dwarfness were recorded by the lines L1 and L9. While, L13 and L2 had the highest mean values towards tallness. Moreover, Line 2 recorded the most desirable estimates for grain quality characters across all environments. The lines L14, L12 and L3 gave the highest grain yield and stress tolerance index (STI), while L6 displayed the lowest grain yield and STI. Moreover, the results indicated that harmonic mean (HM) and yield index (YI) indices gave similar ranks for these lines which considered as water deficit tolerant genotypes. Accordingly, these lines could be used in breeding programs to transmit tolerance genes to commercial cultivars for reduced irrigation.