evaluation of salt tolerance indices in contrast to rice (oryza sativa l.) cultivars and mutants

Salinity is one of the most important and widespread abiotic stresses that limit the growth of crops and productivity. to evaluate the yield and salt tolerance indices in contrast rice genotypes, a factorial experiment was conducted based on a randomized complete block design with three replications in 2022. the treatments included three levels of salinity stress (control, 4 and 8 ds.m-1) and 17 genotypes, including two sensitive and two tolerant check cultivars and 13 advanced (m10) mutant lines. also, the investigated traits in this study were stress tolerance index (sti), stress susceptibility index (ssi), tolerance index (tol), geometric mean productivity (gmp), mean productivity index (mp), and harmonic mean (hm) along with rice paddy yield (py) in both normal and salt stress conditions. the results showed that salinity stress at both levels of 4 and 8 ds.m-1 markedly reduced py in all the studied genotypes. the lowest values of sti (0.04) and tol (-11.79) were recorded in ir29 and deilamani cultivars, respectively. when the cultivars were grown at 4 ds.m-1 of salt stress, the mp10 genotype was superior in terms of gmp (1.32), mp (16.83), and hm (16.05) indices. by comparison, at salinity stress of 8 ds.m-1 the highest values for gmp, mp and hm indices were obtained in the mp10, mp6 and mp10 genotypes with 1.21, 8.32 and 5.42, respectively. cluster analysis at salinity levels of 4 and 8 ds.m-1 showed that the studied mutants have a significant variation in stress tolerance indices. the mp10 mutant line achieved the highest py, which was close to the deilamani tolerant check cultivar when grown at under 8 ds.m-1 of salinity stress. also, this promising line recorded the highest value of tolerance indices in both salinity levels of 4 and 8 ds.m-1. therefore, the advanced mutant line of mp10 could be recommended for further research on salinity stress tolerance mechanisms.

evaluation of salt tolerance indices in contrast to rice (oryza sativa l.) cultivars and mutants

salinity is one of the most important and widespread abiotic stresses that limit the growth of crops and productivity. to evaluate the yield and salt tolerance indices in contrast rice genotypes, a factorial experiment was conducted based on a randomized complete block design with three replications in 2022. the treatments included three levels of salinity stress (control, 4 and 8 ds.m-1) and 17 genotypes, including two sensitive and two tolerant check cultivars and 13 advanced (m10) mutant lines. also, the investigated traits in this study were stress tolerance index (sti), stress susceptibility index (ssi), tolerance index (tol), geometric mean productivity (gmp), mean productivity index (mp), and harmonic mean (hm) along with rice paddy yield (py) in both normal and salt stress conditions. the results showed that salinity stress at both levels of 4 and 8 ds.m-1 markedly reduced py in all the studied genotypes. the lowest values of sti (0.04) and tol (-11.79) were recorded in ir29 and deilamani cultivars, respectively. when the cultivars were grown at 4 ds.m-1 of salt stress, the mp10 genotype was superior in terms of gmp (1.32), mp (16.83), and hm (16.05) indices. by comparison, at salinity stress of 8 ds.m-1 the highest values for gmp, mp and hm indices were obtained in the mp10, mp6 and mp10 genotypes with 1.21, 8.32 and 5.42, respectively. cluster analysis at salinity levels of 4 and 8 ds.m-1 showed that the studied mutants have a significant variation in stress tolerance indices. the mp10 mutant line achieved the highest py, which was close to the deilamani tolerant check cultivar when grown at under 8 ds.m-1 of salinity stress. also, this promising line recorded the highest value of tolerance indices in both salinity levels of 4 and 8 ds.m-1. therefore, the advanced mutant line of mp10 could be recommended for further research on salinity stress tolerance mechanisms.