Influence of sodium chloride on ion accumulation, yield components and fibre characteristics in salt-tolerant and salt-sensitive lines of cotton (Gossypium hirsutum L.)

Three salt-tolerant (B-557, Culture 728-4, MNH-156) and three salt-sensitive cultivars/lines (B-1580 (ne), Culture 604-4, MNH-147) were grown in salinized soil under greenhouse conditions. Four treatments, i.e., control (ECe = 1.6 dS m(-1)), 70, 140, and 210 mol m(-3) NaCl were applied when the plants were three weeks old and the experiment continued until maturity. Dry weights of shoots and roots, and seed cotton yield and yield components were adversely affected by NaCl in all the six lines, but the three salt-tolerant lines yielded more than the three salt-sensitive lines. Ginning out-rum and fibre fineness increased with increasing concentrations of salt, whereas staple length, fibre maturity and fibre strength decreased at higher salt concentrations (140 and 210 mol m(-3) NaCl). The salt-tolerant lines had lower ginning out-turn but higher staple length, fibre: maturity, and fibre strength than those of the salt-sensitive lines. The salt-tolerant and salt-sensitive lines did not differ in leaf or root Na+ concentrations. The salt-sensitive lines accumulated more Cl- in the leaves than all the three salt-tolerant lines at the highest salt level. The salt-tolerant lines had higher concentrations of K+, Ca2+, K/Na ratios and N in the leaves than those of the salt-sensitive lines at the highest NaCl concentration, whereas no relationship could be drawn between salt tolerance and tissue P concentration. The seed oil content of salt-tolerant lines was slightly higher than that of the salt-sensitive lines. From the above results, it was concluded that accumulation of Cl-, K+, Ca2+ and N in the leaves has a positive relationship with the salt tolerance of cotton. But leaf or root Na+ did not show any relationship with the crop salt tolerance. Low ginning out-turn but high staple length, fibre maturity, and fibre strength are associated with the salt tolerance of cotton. (C) 2000 Elsevier Science B.V. All rights reserved.