Evaluation of Ten Egyptian Cultivated Rice Genotypes Tolerance to Drought Stress

Abstract

Drought is a significant limiting factor of rice growth and production, particularly in water scarce locations. To address drought impact on rice growth and development, ten of current cultivated Egyptian genotypes were assessed according to the morphological and physiological traits. Total chlorophyll contents drastically decreased to 100% except Giza 179 (9.66, 54.43% reduction) and Sakha 108 (2.46, 92.63% reduction). Meanwhile, Giza 182 and Sakha Super 300, exhibited minor decreases but remain resilient to stress. Considering growth attributes, drought significantly reduced plant height of all tested cultivars indicating that Sakha 102 is the most sensitive (70.9% reduction) and Sakha 108 is the most tolerant (26.9% reduction). Root fresh weight was drastically reduced in Sakha 102 (97.2%) and Sakha Super 300 (>90%), whereas Giza 178 maintained higher root biomass under stress. Shoot fresh weight also declined markedly, with Sakha 108 and Giza 179 showing the greatest sensitivity (>89%), while Sakha 101 and Sakha 103 exhibited improved performance under moderate stress. Root dry weight reductions were most pronounced in Sakha 102, Giza 177, and Giza 182 (>90%), whereas Sakha 103 and Sakha 104 sustained higher values. Similarly, shoot dry weight decreased in all genotypes, with Sakha Super 300 and Sakha 102 being most affected, while Giza 178 and Sakha 103 maintained relatively higher biomass. Collectively, Giza 178 and Sakha 103 demonstrated superior drought tolerance, highlighting their potential as promising candidates for breeding programs under water-limited conditions.