Morphological analysis and screening of wheat generations derived from HD2967 × Kharchia65 for salt tolerance

ABSTRACT

Aim: To screen wheat generations derived from cross HD2967 × Kharchia65 for two Nax loci imparting salt tolerance and background selection of the plants using polymorphic SSRs.Methodology: The study for salt tolerance was carried out on three generations, i.e., BC1F3, BC2F2 and F4, derived from the cross HD2967 × Kharchia65 in net house. Salt stress was provided at germination stage and the plants were grown to maturity. Data was recorded for various agro-morphological traits which contributed to yield. DNA isolated from young leaves of morphologically superior plants were checked for the presence of Nax1 and Nax2 genes using gene specific primers. Plants having either or both Nax loci were then subjected to polymorphic SSR markers screening for background selection of foreground selected plants. Results: On the basis of agro-morphological performance and presence of either or both Nax genes, 68 high yielding plants were selected. Out of total 178 SSR markers screened covering the whole genome uniformly (A, B and D), 31 markers were polymorphic for the parents HD2967 and Kharchia65. These polymorphic SSR markers were used to produce molecular diversity among the selected progeny plants. Cluster analysis of parents and all the three generations, showed that all the selected plants were inclined towards recurrent parent. Interpretation: This study showed that a linked marker like Nax1 and Nax2 could be a promising tool for breeding wheat with enhanced tolerance to salinity conditions. However, growth rates and biomass production provide reliable criteria for assessing the degree of salt stress and the ability of a plant to withstand it. Therefore, initial screening of seeds in the presence of salt stress provides additional advantage in directional selection. Plants selected with Nax loci, better mean performances, high heritability, and high genetic advance as 5% of mean for the studied traits could be further backcrossed with the recurrent parent to develop salt tolerant wheat lines.