Study of biochemical and chemical traits of different rice genotypes under salinity stress

Salinity is one of the most important obstacles in agriculture which reduces crop production. To investigate the salt stress effect on some biochemical and chemical traits of 11 rice genotypes, an experiment was conducted as split-plot based on randomized complete blocks design with three replications in Agricultural College of Yasouj University, in 2012. The main plots were included 4 levels of salinity (0, 44, 88 and 132 mM NaCl) and subplots were 11 rice genotypes and 10 characteristics including of chlorophyll, soluble sugar, leaf proline, leaf soluble protein, leaf and root sodium, leaf and root potassium, leaf and root sodium to potassium ratio were measured and analyzed. Results showed that genotypes were significantly different for all traits except leaf sodium to potassium ratio at both 5% and 1% probability levels. Positive and significant correlation was observed between leaf proline and soluble sugars in stress conditions. Factor analysis on the basis of principal components method and varimax rotation, extracted 5 factors in non-stress and 4 factors in stress conditions that explained 79.79 and 68.10 percent of total variations, respectively. Using ward's method of cluster analysis, the studied genotypes were grouped in 3 clusters in both non-stress and stress conditions. Results from factor coefficients analysis indicated the importance of stress tolerance component including leaf proline and protein in selection of desirable genotypes for salt stress condition. Considering the results, it could be exploited from heterosis and genetic diversity in breeding programs, using genotypes of the first and third clusters in hybridization because of their maximum difference.