The Effects of Salinity on Yield and Yield Components of Improved Rice Cultivars

Mazandaran province is an important area in rice cultivation but salinity is one thebiggest constraint to obtain crop potential yield in some part of the coastal line of ricecultivated area in northern Iran. In order to find tolerant varieties and study the reactionof some newly released high yielding varieties to different levels of salinity ofirrigation water a Factorial experiment was conducted in a RCD in a greenhouse at theRice Research Institute of Iran, Amol station. 8 varieties, cultivated in pots, were testedwith 3 levels of salinity (2, 4 and 6 dS.m-1) along with control (S0: EC=1 dS.m-1) with 3replications. Results showed that salinity had adverse effects on yield, number of tillersper pot, filled and unfilled spikelets, fertility, 100 grain weight, but increased number ofunfilled tillering. Relative yield in salinity treatment in comparison with fresh waterwere 23, 63 and 85 percent, respectively. The average of rice yield loss threshold wascalculated 1.3 dS.m-1. In average, number of panicle and no. of filled spikeletsaccounted for 80 and 59% of total variation of grain yield, but it decreased by increasingin salinity level. There was a high correlation between yield and number of panicle andgrain weight per panicle. The results showed that the yield in each salinity level couldbe predicted by number and weight of panicle (r2= 0.85)