The identification of wheat leaf rust resistance genes and their utilisation value in 42 wheat cultivars

Leaf rust isan important wheat disease that considerably reduces the wheat production inmost wheat growing regions worldwide. This study aimed toidentify leaf rust resistance genes in42 wheat varieties tofind genetic sources with the broadest spectrum ofresistance against leaf rust pathotypes, toenable effective breeding for disease resistance. Inthis study, 42 wheat cultivars were inoculated with 18 pathotypes ofPuccinia triticina Eriks. atthe seedling stage topostulate the Lr genes inthe cultivars. Resistance toleaf rust atthe adult stage was then tested infield trials under natural infection during the 2019 to2020 cropping seasons atBaoding, Hebei Province. Gene postulation together with molecular marker detection identified ten Lr genes (Lr1, Lr10, Lr14a, Lr26, Lr2a, Lr17, Lr20, Lr34, Lr37, and Lr46) among the 42 accessions. Lr1 was present in16 accessions, Lr14a inthree accessions, Lr17 infive accessions, Lr2a infive accessions, Lr34 inone accession, Lr10 intwo accessions, Lr37 intwo accessions and Lr46 in 29 accessions. Additionally, 15 wheat accessions displayed adult-plant resistance or other unknown genes. These results suggest that a high level of leaf rust resistance can be achieved by combining known resistance genes and adult-plant resistance genes in wheat cultivars.