Combining Ability and Heterosis for Yield, Fiber Quality and Physio-Chemical Parameters in Cotton Under Salt Stress

Abstract

Background: There are several abiotic stresses that can limit the yield of cotton crops. Among those stresses, salinity is one   that significantly reduces crop productivity. The primary purpose of this research was to explore the breeding potential of cotton genotypes for salinity tolerance. Results: For this purpose, the salt-tolerant genotypes, NIAB-545, CIM-595, Coker-307, FH-113, FH-942, DNH-40 and salt sensitive genotypes Cyto-178, VH-363, FH-326 were grown under field conditions. These accessions were hybridized in a Line × Tester mating design to identify the genetic components of yield-contributing traits under control, 10 dSm^-1, 15 dSm^-1 and 20 dSm^-1 salt stress conditions. Significant levels of variation were found among the genotypes for root and shoot length, fresh shoot and root weight, dry root and shoot weight, Na⁺, K⁺ and K⁺/Na⁺, proline, H₂O₂, POD and CAT.  Analysis of variance indicated that there were significant differences among genotypes for these traits.  Salt stress caused a reduction in all traits except Na⁺, GOT, H₂O₂, and proline. Non-additive gene action was found for yield, fiber, ionic, and biochemical traits except for Na⁺ ions. The proportional contribution to total variance for all traits was found to be maximum in lines and lower for testers. Among the lines, FH-942 was found to be the best general combiner for plant height, number of bolls, and seed cotton yield under control, 10 dSm^-1,15 dSm^-1 and 20 dSm^-1 conditions. NIAB-545 was the best general combiner for fiber fineness, fiber length, fiber strength, GOT and catalase under control, 10 dSm^-1 and 15 dSm^-1 and 20 dSm^-1 salt stress. The FH-942 genotype also showed greater general combining ability (GCA) effects for K⁺, proline and CAT under control and salt stress conditions. Among the testers, FH-326 was best general combiner for most traits, while Cyto-178 had positive and significant GCA effects for fiber fineness, fiber length, fiber strength, POD and catalase under control and salt stress conditions. Conclusion: The cross combination FH-942×FH-326 showed positive and significant specific combining ability effects for most of the traits and exhibited significant heterosis for most of studied traits. The selected hybrid can be effectively utilized in breeding programs aimed at improving salt tolerance in cotton.