Document Type : Original research
10.12816/ejpb.2025.466067
Abstract
Salinity is a crucial abiotic stress that severely limits rice growth and production, particularly under the current severe climate changes. Consequently, cultivation of new salt-tolerant rice genotypes is one of the best strategies to sustain rice production. This study aimed to evaluate the physiological and agronomic performance of diverse rice genotypes under both normal and saline soil conditions, identify promising and salinity-tolerant rice genotypes, and assess the molecular genetic diversity among the evaluated genotypes using Sequence Tagged Microsatellite Site (STMS) markers. Seventeen rice genotypes were evaluated at Sakha Agricultural Research Station, which represents normal soil conditions, and at the El-Sirw Agricultural Research Station, which represents saline soil conditions, during 2023 and 2024 growing seasons. The obtained results indicated highly significant variation among the years, environments, genotypes and their interactions for most studied traits. Salinity stress substantially decreased relative water content (RWC), plant height, spikelet fertility percentage, grain yield, and its attributes. Conversely, it significantly increased malondialdehyde (MDA) content, proline content, and antioxidant enzyme activities (APX and SOD) compared to normal conditions. The genotypes Giza178, L1, L6, and L4 recorded the highest values of RWC, proline content, APX, and SOD activity under salinity stress conditions, respectively, reflecting their enhanced physiological adaptability and resilience to salinity. Additionally, the genotypes L10, Sakha Super-301, Sakha Super300, had the highest grain yield under normal conditions, while L4, GZ1368-S-5-4 and Giza178 exhibited the highest grain yield under salinity stress conditions. In contrast, the lowest grain yield was recorded in the genotypes L8, L3, and L7 under both conditions. Moreover, the genotypes Giza178, L10, Sakha Super300, GZ1368, and L4 exhibited the highest stress tolerance index (STI) and yield index (YI), indicating their potential as salt-tolerant genotypes. Consequently, these tolerant genotypes could be utilized in the future rice breeding program for enhancing grain yield under salinity stress conditions. The molecular analysis with 16 STMS markers revealed detection of 272 total amplified fragments representing 45 alleles across the tested materials. The detected alleles ranged from 1 allele for RM223 to 4 alleles in RM10852, RM8094and RM 10772with an average of 2.8 alleles per locus. The polymorphic information content (PIC) ranged from 0 for RM223 (monomorphic marker), to 0.73 for RM8094.The nearby position of tolerant genotypes (Giza 178, GZ1368and Sakha Super 300) in cluster analysis proves the ability of STMS molecular markers to identify salt tolerant genotypes that co-linear with most studied parameters and indices. The study demonstrates the power of STMS markers in detecting molecular diversity of the tested genotypes and the existence of considerable amount of diversity.
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