Marker-trait association of Russian wheat aphid (Diuraphisnoxia) resistance in the global diversity set of wild barely

Russian wheat aphid (RWA, Diuraphis noxia Kurdjumov), a common pest on barley around the world, can severely damage barley yield and grain quality. The present study aimed to identify simple sequence repeat markers associated with RWA resistance in wild barley (Hordeum vulgare subsp. spontaneum). A panel of 30 wild barely accessions was selected from the ICARDA gene bank and Iran to represent 10 Asia countries scattered along the natural geographic distribution of the species for RWA resistance. Five traits including leaf chlorosis, leaf rolling, chlorophyll a, b, and total chlorophyll concentration were evaluated. Fourteen SSR markers were used to study genetic diversity. The relationship of 52 polymorphic SSR markers with the associated RWA resistance traits was tested using general linear model (GLM) and mixed linear model (MLM) approaches. The population structure analysis revealed seven subpopulations in the entire collection (K=7). Eleven trait marker-trait associations (MTA) were identified on chromosomes 1H, 2H, 3H, 4H, and 7H. Markers Bmag007, Bmag6, Bmac0399, Bmag0125, and EBmac0701 which exhibited significant associations with RWA resistance traits. All five markers were associated with traits in both GLM and MLM analyzes. This study identified novel genomic regions putatively linked with RWA resistance traits, which could be further investigated for shedding light on the genetic architecture of RWA resistance in barley. The findings could be useful for using the RWA resistance accessions of H. spontaneum as parents for breeding barley cultivars.