Evaluation of some rice (Oryza sativa L.) genotypes under drought stress conditions by using morphological, physiological and molecular characteristics

Abstract

Drought is a major challenge, affecting rice at the morphological, physiological, biochemical and molecular levels. This study was conducted to compare eight cultivars of rice (Oryza sativa L.) for drought tolerance based on some morphological, physiological and molecular tests at the seedling stage. Drought stress was imposed by four levels of polyethylene glycol (PEG) 0, 5, 10 and 15% for 5 days. After 5 days, where seeds of all concentrations were watered daily with tap water for 21 days, plant samples were taken for measurements. Seeds from all cultivars treated with 15% PEG recorded complete germination (100%) for both G179 and Hageen Masry, while the other varieties recorded germination ranged between 56.7 and 83.30. At 10% PEG, a decrease in chlorophyll a, b, carotenoids, proline and shoot length was observed. This result indicates that Hageen Masry showed the best performance under drought stress due to its own nature of tolerance. For PCR analysis, a total of 47DNA fragments were detected; Among them, 33 are polymorphic, and 9 bands are monomorphic. To determine the level of polymorphism in the analyzed set of the eight rice genotypes, the percentage of polymorphic bands ranged from 20% to 100% with an average of 73.4%. The amplified DNA bands ranged in size from 100 to 1500 bp. The SCoT-2 primer was the most polymorphic, while the lowest number of amplified polymorphic fragments (1) was detected by primers SCoT-5 and SCoT-6. The polymorphic information content (PIC) value ranged from 0 to 0.374, with an average of 0.26.