Intra-specific variation for salt tolerance in cotton (Gossypium hirsutum L.)

Abstract

Response of eighty local and exotic cultivars/lines to salt stress was assessed at germination, 0, 70, 140 mol m??? NaCl concentrations, and seedling at 0 or 140 mol m??? NaCl. Differential varietal response towards increasing salinity was observed. In the germination experiment, twenty-six cultivars were placed in the tolerant group having germination range from 50.07 to 64.18 percent. The moderately tolerant group had 36 cultivars/lines with germination range of 40.58 to 49,99 percent, whereas the moderately sensitive group displayed the germination range from 31.23 to 39.99 percent. The sensitive group included only three cultivars, MNH-147, Culture-604-4, and B-1580 (ne). On the basis of percent shoot dry weight, the tolerant group had more than 70 percent dry weight of control. The moderately tolerant group ranged from 50.0 to 70,0 percent in percent shoot dry weights, and the sensitive group comprised six cultivars/lines which had less than 50 percent shoot dry weight. In order to determine weather salt tolerance at two initial growth stages is conferred upon the adult stage, three highly salt tolerant cultivars/lines, B557, MNH156 and Culture 728-4 and three most salt sensitive B 1580 (ne), MNH147 and culture604-4 were tested at adult stage in soil salinised with 0 (control), 70, 140 and 210 140 mol (sic) NaCl. Seed cotton yield and yield components were adversely with salt stress. The tolerant cultivars/lines produced significantly better yield than those of the salt sensitive. From these studies, it can be easily concluded that there is a considerable variation for salt tolerance in cotton which can be exploited by selection and breeding for improving salt tolerance in this crop. Hence salt tolerance in this crop does not vary at different growth stages, selection for salt tolerance at initial growth stages could be effective.