The potential of breeding Gossypium hirsutum L. for salinity tolerance

Abstract

Salinity is an abiotic stress that can significantly reduce the crop productivity. The primary purpose of the research was to explore the breeding potential of cotton for salinity tolerance. For this purpose, 50 cotton genotypes were grown at control, 10 dS m-1 and 15 dS m-1 salt stress conditions at seedlings stage. Variations were observed for all the genotypes for chlorophyll contents, root and shoot length, fresh shoot and root weight, dry root and shoot weight, Na+, K+ and K+/Na+. The genotypic and phenotypic coefficient of variance was moderate to high, heritability and genetic advance was also high, which indicated that genotypes can be improved for salinity tolerance at seedlings stage through selection. The genotypes that performed better for the characters having high heritability were selected as tolerant genotypes whereas the genotypes that performed poor for characters were considered salt sensitive. NIAB-824, FH-312, FH-118, MNH-992, CIM-612 and KEHKSHAN were found salt tolerant and SB-149, BS-80 and FH-114 were found salt sensitive genotypes. The Line × Tester mating design was used to find out the genetic components for yield (Plant height, Number of bolls, boll weight and seed cotton yield), fiber traits (fiber fineness, fiber strength, fiber length and ginning out turn), ionic traits (Na+, K+ and K+/Na+) and physiological traits (H2O2, SOD, POD, CAT and TSP) at control, 10 dSm-1 and 15 dSm-1 salt stress conditions. Analysis of variance indicated that there were significant differences among genotypes. The salt stress caused the reduction in all traits except Na+, ginning out turn percentage, H2O2 and SOD. Non- additive gene action was found for yield, fiber, ionic and physiological traits except Na+ ions which indicated the additive gene action. Proportional contribution to total variance for all the traits was maximally contributed by the lines whereas tester’s contribution was less. Among lines, KEHKSHAN was the best general combiner for plant height, number of bolls and seed cotton yield under control, 10 dSm-1 and 15 dSm-1 and FH-312 was best general combiner for fiber fineness, fiber length, fiber strength, ginning out turn percentage and catalase under control, 10 dSm-1 and 15 dSm-1 salt stress and FH-118 had highest GCA effects for K+ concentration, SOD and TSP under control and salt stress. Among testers FH-114 was best general combiner for most of the traits. SB-149 had positive significant GCA effects for fiber fineness, fiber length, fiber strength, POD and catalase under control and salt stress. KEHKSHAN×FH-114 had positive and significant specific combining ability effects for most of the traits and hybrid KEHKSHAN × FH-114 also indicated highly significant mid-parent and better parent heterosis for most of the studied traits. The selected hybrid can be utilized in the future breeding programs against salt stress.