Evaluation of reaction of some rice (Oryza sativa L.) genotypes to salinity stress at seedling stage

Rice is one of the most important crops in Iran and all over the world, and Salinity stress is a significant limiting factor in producing this crop. In this experimen 11 rice genotypes as split-plot based on randomized complete block design with three replications in summer 2012, at the college of Agriculture, at Yasouj University. The main plot of salinity at 4 levels (0, 44, 88 and 132 mM) and subplot were 11 rice genotypes, include: Gharib, Local Yasouj, Champa and Shahri Loudab, 304, Lenjan- Askari, Kamfirooze, Domsiah Mamasani, Mossa-Tarom, Hassan-Seraei, and Dollar. Triats evaluated consist of flouresance cholorophyll indices (F0, Fm, Fv and Fv/Fm, respectively), cholorophyll soluble sugars, proline and protein leaf and grain yield. The results analysis of variance showed that the traits of chlorophyll fluorescence indices (F0, Fm, Fv and Fv/Fm, respectively), chlorophyll, soluble sugars, and proline and leaf protein were affected by interaction of salinity and genotype. With increasing tension stress, proline accumulation, protein and leaf soluble sugars increased in plants under salinity levels, but genotypes differed in this regard. Increasing salt stress levels reduced the relative chlorophyll content and grain yield. Mean of comparison rice genotypes showed that the highest grain yield belonged to Lanjan askari genotype and the lowest was genotype Dollar. Cluster analysis with minimum variance Ward's method in salinity stress conditions classified all genotypes in four groups and the highest genetic distance was observed between cluster 1 and cluster 4, that can from genotypes this two cluster for breeding program like hetrosis and transgrissive segregation used.