Submitted to: G3, Genes/Genomes/Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2016
Publication Date: 4/1/2017
Citation: Thompson, A.L., Mahoney, A.K., Smiley, R.W., Paulitz, T.C., Hulbert, S., Garland Campbell, K.A. 2017. Resistance to multiple soil-borne pathogens of the Pacific Northwest is co-located in a wheat recombinant inbred line population. G3, Genes/Genomes/Genetics. 7: 1109-1116. Interpretive Summary: Soil-borne pathogens are a major constraint to yield for dryland wheat (T. aestivum L.) production in the Pacific Northwest. Challenges associated with phenotyping resistance to many soil-borne pathogens make these traits ideal candidates for quantitative trait loci (QTL) mapping for marker-assisted breeding strategies. In this study, QTL associated with reduced disease symptomology to four soil-borne pathogens were found to be co-localized on the 5A wheat chromosome. This co-localization indicates a passive mechanism of resistance has been identified and will be useful for breeding resistance to multiple soil-borne pathogens.
Technical Abstract: Soil-borne pathogens of the Pacific Northwest decrease yields in both spring and winter wheat. Pathogens of economic importance include Fusarium culmorum, Pratylenchus neglectus, P. thornei, and Rhizoctonia solani AG8. Few options are available to growers to manage these pathogens and reduce yield loss, therefore the focus for breeding programs is on developing resistant wheat cultivars. A recombinant inbred line population (MP-7, NSL 511036) was developed to identify quantitative trait loci associated with resistance to P. neglectus and P. thornei. This same population was later suspected to be resistant to F. culmorum and R. solani AG8. This study confirms partial resistance to F. culmorum and R. solani AG8 is present in this population. Six major and 16 minor quantitative trait loci were identified across seven measured traits. Four of the six major quantitative trait loci were found within the same genomic region of the 5A wheat chromosome indicating a passive non-specific mechanism contributes to the resistance. These quantitative trait loci will be useful in breeding programs looking to incorporate resistance to soil-borne pathogens in wheat cultivars.