Response of Rice to Different Salinity Levels during Different Growth Stages

摘要

Salt accumulation in irrigated soils is one of the main factors that diminish crop productivity since most of the crops are not halophytic. A greenhouse experiment was conducted in Rasht, North of Iran during May to June 2010 as a complete randomized block design with three replications. The treatments in this study were application of four levels of saline irrigation water (2,4,6 and 8 dS/m, respectively) at four growth stages (tillering, panicle initiation, panicle emergence and ripening). The aim of this study was to determine the effect salinity levels on some agronomic characters of rice. The results of this study showed that increase in salinity levels of irrigation water significantly decreased length of filled panicle, number of filled grains per filled panicle, number of spikelets per filled panicle and total number of spikelets per panicles but effect of different salinity levels on percentage of ratio of filled panicle number to tiller number and percentage of ratio of yield to straw weight was not significant. The least of these yield components were observed at the highest salinity level (8 dS/m). In different growth stages of rice, all yield components were different. Final growth stages, i.e., panicle emergence and ripening showed less sensitivity to salinity but primary stages, i.e., tillering and panicle initiation were more sensitive to salinity. Therefore, irrigation with saline water can be used in the final stages of plant growth, i.e. panicle emergence and ripeness.