泛喜马拉雅地区条形柄锈菌小麦专化型毒性多样性OA

To clarify the virulence structure of Puccinia striiformis f.sp.tritici(Pst)in the Pan-Himalayan region,a total of 297 isolates was collected during 2024-2025 from China(Xizang,Yunnan,and Qinghai),as well as India,Pakistan,Afghanistan,and Nepal.These isolates were purified and characterized using wheat near-isogenic lines carrying different Yr resistance genes for physiological race identification and virulence phenotype diversity analysis.In total,35 known physiological races and 82 previously unreported races were identified,of which PSTv-076 was the predominant race,accounting for 18.52%of the isolates.Among all tested isolates,virulence frequency was highest to Yr6(96.63%),whereas no isolate virulent to Yr5 was detected.Virulence diversity analysis showed that the China(eastern Xizang)population(G5)exhibited the highest values for all diversity indices.In contrast,the Afghanistan population(G1)had the lowest Nei's diversity index(Hs)and Kosman index(K),the India-Nepal-China(western Xizang)population(G2)showed the lowest values for Simpson index(Si),normalized Shannon index(Sh),Stoddart index(St),Shannon index(SH),and richness(E),and the Pakistan population(G3)had the lowest Gleason index(G).Cluster analysis based on virulence phenotypes revealed that the China(Qinghai)population(G4)was the most distinct and formed an independent cluster,whereas the remaining five populations grouped into another major cluster.Within this cluster,the Afghanistan(G1),India-Nepal-China(western Xizang)(G2),and Pakistan(G3)populations showed highly similar virulence structures and formed a subcluster,while the China(eastern Xizang)(G5)and China(Yunnan)(G6)populations were successively clustered on the periphery.These findings elucidate the physiological race composition and virulence structure of Pst populations in the Pan-Himalayan region and provide a theoretical basis for the rational deployment of wheat cultivars carrying effective resistance genes in this area.