Genetic Analysis Reveals Relationships Among Populations of Puccinia triticina from Henan Province of China

Wheat leaf rust, caused by Puccinia triticina Erikss. (Pt), is a major foliar disease that poses a significant threat to wheat production in Henan Province, a major wheat-growing region of China. Elucidating the population genetic structure of Pt is critical for predicting pathogen dispersal trends and guiding disease management. In this study, 384 Pt isolates collected from 13 locations in Henan were genotyped using 11 polymorphic simple sequence repeat (SSR) loci. A total of 204 multilocus genotypes (MLGs) were identified. The Sanmenxia (SMX) population exhibited the highest genetic diversity (H = 3.42; G = 30.12; λ = 0.967), while Shangqiu (SQ) showed the lowest (H = 2.09; G = 4.59; λ = 0.782). Analysis of molecular variance (AMOVA) revealed that 87% of the total genetic variation occurred within populations and 13% among populations. Population structure analyses consistently separated the 13 populations into two genetic clusters, with Xinyang (XY) and SQ forming one distinct group and the remaining 11 populations from the western, central, and northern regions constituting the other. The relative migration network further supported this pattern, showing a highly interconnected network among the central and western populations, but with XY and SQ forming an isolated subnetwork.