Tolerances of seven diverse genotypes of cotton (Gossypium hirsutum L.) and their 21F1 progenies were evaluated in non-saline and saline environments. Adding incremental levels of NaCl to Hoglands solution in a sand culture electrical conductivity of 24 dS m1 was attained inducing salinity Stress. Combined analysis based on two salinity levels revealed significant salinity-level effects for shoot dry weight, plant height, shoot fresh weight and contents of ions in shoot tissues, including sodium (Na+), potassium (K+), calcium (Ca2+), K+/Na+, Ca2+/Na+, shoot dry weight/shoot fresh weight (SDW/SFW), root length/shoot height (RL/SH). Salinity had no significant effect on root length. Estimation of Stress Intensity (SI) indicated larger values for shoot fresh weight, plant height, Ca2+/Na+, K+/Na+ (0.27, 0.31, 0.39 and 0.55, respectively). Negative and high index of SI for Na+ indicated that its mean in a saline environment was more than two times from the mean in a non-saline environment. Low estimates of negative SI index for root length, Ca2+, SDW/SFW and RL/SH indicated the effects of a saline environment for these traits were better than the other traits. Significant interactions of genotypes and salinity levels were observed for all studied traits. The result of factor analysis based on minimum eigenvalue by means of principle component analysis extraction method and rotation method of Varimax with Kaiser Normalization revealed four factors for eleven studied traits in a saline environment. Factor one and two were detected as morphological and nutritional factors, respectively. Factor three and four were detected as morphological and nutritional factors dependent on their high coefficients factor loading simultaneously. The results of factor analysis indicated that selection for morphological traits, specifically; that selection based on K+, Ca2+ and K+/Na+ should be more efficient than other traits. Cluster classification of genotypes on the basis of value of four principal for each genotype by means of principle component analysis of correlation matrix distinguished genotypes SahelxBelizovar, Siokra and SindosexKoker from other genotypes in salinity tolerance. On the basis of low estimates of the tolerance index (TOL) for shoot dry weight (its large value represents more sensitivity to stress), it was concluded that the above genotypes have had suitable salinity tolerance in early stages of growth. PDFFulltextXMLReferencesCitation
How to cite this article
Gholamhossein Hosseini and Ratnakar J. Thengane, 2007. Salinity Tolerance in Cotton (Gossypium hirsutum L.) Genotypes. International Journal of Botany, 3: 48-55.