Molecular and Phenotypic Analysis of Bread Wheat Varieties in Relation to Durable Rust Resistance

Abstract

Global wheat production is constantly threatened by rust diseases. Identifying resistant genes is a useful tactic to control wheat rust pathogen. Twenty-six wheat varieties were screened with twelve Simple Sequence Repeats (SSR) markers to detect rust resistant genes and the efficacy of genes was validated through field testing. The alleles Lr32, Lr39, Lr50, SrCad and SrWeb were not amplified in the varieties included in this study. The SSR markers indicated that the varieties viz., Chakwal-97, Bakhar-2002 and Lasani-2008 had a combination of 02 slow rusting alleles (Lr46/Yr29 and Yr18/Lr34). The adult plant resistance (APR) allele Yr17 was less prevalent and found only in BWL-97. However, Noshera-96 had a slow rusting combination of Lr67/Yr46 and Lr46/Yr46 alleles. The Lr46/Yr29 identified in 50% of the varieties, Yr18/Lr34 in 19.23%, Lr32 in 11.54%, and multiple APR alleles in 19.32%. Their resistance was validated through a field trap nursery for 3 consecutive seasons. The slow rusting combination of Lr46/Yr29 and Yr18/Lr34 was comparatively more effective than Lr67/Yr46 and Lr46/Yr29 alleles under field conditions. The varieties Yecora-70, Lylpure-73 and Tandojam-83 showed highly susceptible phenotype. The varieties Chakwal-86, Pirsabak-2005, Fareed-2006, and Sehar-2006 showed resistant to moderately resistant phenotype at high-temperature adult-plant stage. The cluster diagram divided the varieties into two distinct clades. The clade II depicted the abundance of APR allele Lr46/Yr29. The varieties contain valuable sources of durable rust resistant alleles that can be exploited to deploy rust resistance in future wheat cultivars. It has been observed that the varieties approved for commercial cultivation after 1990s and onwards contain APR alleles. © 2021 Friends Science Publishers