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

Leaf rust is an important wheat disease that considerably reduces the wheat production in most wheat growing regions worldwide. This study aimed to identify leaf rust resistance genes in 42 wheat varieties to find genetic sources with the broadest spectrum of resistance against leaf rust pathotypes, to enable effective breeding for disease resistance. In this study, 42 wheat cultivars were inoculated with 18 pathotypes of Puccinia triticina Eriks. at the seedling stage to postulate the Lr genes in the cultivars. Resistance to leaf rust at the adult stage was then tested in field trials under natural infection during the 2019 to 2020 cropping seasons at Baoding, 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 in 16 accessions, Lr14a in three accessions, Lr17 in five accessions, Lr2a in five accessions, Lr34 in one accession, Lr10 in two accessions, Lr37 in two 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.