Evaluation of relationship between some traits of Iranian rice (Oryza sativa. L.) seedlings under saline conditions

In order to evaluate the relationships between some traits of Iranian rice seedlings under saline conditions,,75 Iranian cultivars as traditional, improved and introduced cultivars were used, as a randomized complete block design experiment with 3 replications at Rice Research Institute of Iran in three levels of salinity (normal, 1.2, 4 and 8 dS.m-1) in 2006. Root and shoot length, root and shoot dry weight, Na+ and K+ concentration in shoot and genotypic code (based on IRRI protocol) were recorded. Tolerant cultivars had high biomass (root and shoot dry weight) and low Na+/K+ ratio. Negative and significant correlations were detected among shoot dry weight, biomass and genotype code, while positive and significant correlations were seen among Na+ concentration, Na+/K+ ratio and genotype code in 4 and 8 dS.m-1 levels. Significant and robust correlations were seen between mean productivity index (MP), tolerance index (TOL), stress tolerance index (STI), stress susceptibility index (SSI) and harmonic mean (HM) for Na+ and mean productivity, stress tolerance index and stress susceptibility index for Na+/K+ ratio with genotypic code (P<0.05). Path analysis for 4 dS.m-1 showed that shoot dry weight had a high direct effect on genotypic code. Although biomass had low direct effect on genotypic code, but had high indirect effect on genotypic code via shoot dry weigh. Factor analysis revealed that biomass, shoot dry weight and K concentration explained the most of the total variation.