بررسی تحمل شوری در یک جمعیت تلاقی برگشتی پیشرفته برنج براساس غلظـت برخی مواد معـدنی در مرحله گیاهچه

The objective of the present research was to investigate the effect of salinity stress on sodium, potassium and calcium concentrations, and Na+/K+ and Na+/Ca2+ ratios at seedling stage in an advanced back cross (BC2F6) rice population. The population was derived from crossing between Hashemi, an Iranian cultivar, and IR67418-110-32222 (IR-22) from IRRI. The ANOVA indicated that the effects of genotypes, salinity stress and interaction between stress and genotype were significant for all the traits, which is suggestive of high level of genetic variation, salinity effect on traits and different response of the genotypes to salinity levels. The salinity stress markedly decreased the K+ concentration in the shoot. However the shoot Na+ and Ca2+ concentration and Na+/K+ and Na+/Ca2+ ratios were significantly increased in saline environment. The population characteristics mean value were found to be between of parents values and it often shifted to recurrent parent (Hashemi) value in both stress and non stress conditions. It shows that Hashemi variety gene’s leave more influences on the expression of the traits in the population. Transgressive segregation was observed for all the studied traits in the population lines. Genetic and phenotypic correlations among the studied traits showed the same trend. The highest correlation coefficients were related to Na+ concentration and Na+/K+ (rg= 0.89**) in non stress condition. The high heritability levels of the traits provide selection possibility for salinity tolerance in the population based on these traits. According to the present findings, it is possible to candidate some lines (such as line number 139) as salt tolerant at the seedling stage.