Salinity Tolerance Indices of Barley, Cotton, Canola, and Forage Sorghum Cultivars

Salinity stress is one of the most important problems in agriculture sector, especially in dry and semi-dry land regions of the world. To evaluate salt tolerance of different varieties of barley, cotton, canola, and forage sorghum, some experiments were conducted in Salinity Research Farm, National Salinity Research Center, Yazd, Iran. Species and cultivars included barley (Rodasht, Afzal. Line1 and Line4), cotton (Siokra, Bakhtgan and Varamin varieties), canola (Hyola401, Hyola420, Rindow, Zarfam, SLM, Sarigol, Talent, Option500, Option501, RGS, Opera, Elite, Mozart, CV.Star, CV.Roby, SYN, Milena, Okapi and GoldRush), and forage sorghum (KFS1, KFS2, KFS3, KFS4, Speedfeed, Sugargraze, Jumbo, and Nectar varieties). These were tested by irrigated water treatments with salinity of 2 to 14 dS.m-1for two years. Results of the experiments showed that there were some inter and intra species differences in salinity tolerance. Generally, salinity tolerance indexes of barley and cotton were 18.70 and 13.80, respectively. The parameter C50, which indicates 50 percent reduction in yield, was 18 and 12.6 dS/m for barley and cotton, respectively. The salinity tolerance threshold values of the barley and cotton species were 3.6 and 4.6 dS/m, respectively, based on two linear models. The slope of decreasing yield for this species was 3.6% and 5.7%, respectively. The most salinity tolerant variety among the studied varieties were Rodasht for barley, Siokra for cotton, varieties Hyola420, Hyola401, Option501, Mozart and RGS for canola, and Speedfeed for hybrid sorghum and Line KFS3 for local varieties of sorghum. It should be noted that, for selection of tolerant varieties, in addition to threshold values, other parameters like absolute yield, STI and Tol indices need to be considered.