Identification of a molecular marker linked to an Agropyron elongatum‐derived gene Lr19 for leaf rust resistance in wheat

Abstract

Abstract The leaf rust resistance gene Lr19 , transferred from Agropyron elongatum into wheat ( Triticum aestivum L.) imparts resistance to all pathotypes of leaf rust ( Puccinia recondita f.sp. tritici ) in South‐east Asia. A segregating F 2 population from a cross between the leaf rust resistant parent ‘HW 2046’ carrying Lr19 and a susceptible parent ‘Agra Local’ was screened in the phytotron against a virulent pathotype 77‐5 of leaf rust with the objective of identifying the molecular markers linked to Lr19 . The gene was first tagged with a randomly amplified polymorphic DNA (RAPD) marker S73 728 . The RAPD marker linked to the gene Lr19 which mapped at 6.4 ± 0.035 cM distance, was converted to a sequence characterized amplified region (SCAR) marker. The SCAR marker (SCS73 719 ) was specific to Lr19 and was not amplified in the near‐isogenic lines (NILs) carrying other equally effective alien genes Lr9, Lr28 and Lr32 enabling breeders to pyramid Lr19 with these genes.