Morpho-physiological characterization of bread wheat genotypes and their molecular validation for rust resistance genes Sr2, Sr31 and Lr24

Abstract

Leaf rust caused by Puccinia recondita and stem rust by Puccinia graminis triticii are among the most destructive diseases of wheat worldwide. The selection of genotypes carrying two or more genes using traditional host-parasite interaction is very time consuming and often not possible due to lack of isolates with specific virulence and difficulty of identifying one seedling resistance gene in the presence of another gene. Identification of molecular markers for resistance genes can facilitate selection of gene positive plants at early stage to complete the study in short time and cost effective manner. In current investigation assessment of 51 diverse genotypes of wheat (Triticum aestivum L.) was carried out using 16 morpho-physiological yield attributing traits. Biological yield was found highly correlated and positively significant with grain yield (r = 0.410) and spike length (r = 0.601) at 1% significant level. It was significantly correlated with number of grains per spike (r = 0.333) and canopy temperature (r = 0.325) at 5% significant level. Validation of genes Lr24, Sr31 and Sr2 in these genotypes was done using gene specific Sequence Characterized Amplified Region (SCAR) and Simple Sequence Repeats (SSR) markers. The SSR marker Xgwm533 showed highest genetic diversity (0.6290) and PIC value (0.5542), whereas the SCAR primer SCS30.2 and SCSS26.1 revealed lowest gene diversity (0.1769) and PIC value (0.1612). The major allele frequency for Xgwm533 was observed (0.4706) which is lowest; while primer SCS30.2 and SCSS26.1 showed highest major gene frequency (0.9020).