Mapping of barley susceptibility/resistance QTL against spot form net blotch caused by Pyrenophora teres f. maculata using RIL populations

Authors: TAMANG, PRABIN - North Dakota State University; RICHARDS, JONATHAN - North Dakota State University; ALHASHAL, ABDULLAH - North Dakota State University; POUDEL, ROSHAN - North Dakota State University; HORSLEY, RICHARD - North Dakota State University; Friesen, Timothy; BRUEGGEMAN, ROBERT - North Dakota State University

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2019
Publication Date: 3/20/2019
Citation: Tamang, P., Richards, J.K., Alhashal, A., Poudel, R.S., Horsley, R.D., Friesen, T.L., Brueggeman, R.S. 2019. Mapping of barley susceptibility/resistance QTL against spot form net blotch caused by Pyrenophora teres f. maculata using RIL populations. Theoretical and Applied Genetics. 132(7):1953-1963. https://doi.org/10.1007/s00122-019-03328-x.
DOI: https://doi.org/10.1007/s00122-019-03328-x

Interpretive Summary: Malting barley production is seriously hampered by fungal diseases that attack the leaf area of the seedling and adult plant, resulting in less photosynthetic area available for grain filling and therefore reduced yield and quality. Spot form net blotch of barley is arguably one of the most destructive leaf disease of barley in the US and worldwide. Identification and characterization of resistance to spot form net blotch is critical to both understanding the disease and providing genetic resources to geneticists and breeders to solve the disease problem. In this study, we generated three barley mapping populations that could be used for the identification of genetic loci contributing resistance to spot form net blotch. Twelve resistance loci were identified and molecular markers potentially useful in breeding were identified. This information is critical to breeders trying to introgress resistance into locally adapted barley cultivars. Both Germplasm and molecular markers are already being used by barley geneticists and breeding programs in the Northern Great Plains.

Technical Abstract: Spot form net blotch (SFNB) caused by the necrotrophic fungal pathogen Pyrenophora teres f. maculata (Ptm) is an important disease of barley worldwide including the major barley production regions of North America. To characterize SFNB resistance/susceptibility quantitative trait loci (QTL), three recombinant inbred line (RIL) populations were developed from crosses between the malting barley cultivars, Tradition (six row) and Pinnacle (two row), and the two world barley core collection lines, PI67381 and PI84314. Tradition and Pinnacle were susceptible to many North American Ptm isolates, while PI67381 and PI84314 carry resistances to diverse Ptm isolates from across the globe. The RIL populations, Tradition/PI67381, Pinnacle/PI67381, and Pinnacle/PI84314 were genotyped using polymerase chain reaction-mediated genotype-by-sequencing single nucleotide polymorphism marker panels and phenotyped at the seedling stage with six geographically distinct Ptm isolates: FGOB10Ptm-1 (North Dakota, USA), Pin-A14 (Montana, USA), Cel-A17 (Montana, USA), SG1 (Australia), NZKF2 (New Zealand) and DEN2.6 (Denmark). The goal was to determine if the susceptible elite lines contained commonsusceptibility genes/QTL or if the resistant lines had common resistant genes/QTL effective against diverse Ptm isolates.The QTL analyses identified a total of 12 resistance and/or susceptibility loci on chromosomes 2H, 3H, 4H, 6H, and 7H of which three had not been previously reported. Common major QTL were detected on chromosome 2H (R2 = 14–40%) and7H (R2 = 24–80%) in all three RIL populations, suggesting underlying genes with broad resistance specificity. The major 7H QTL was shown to be a dominant susceptibility gene in both susceptible malting barley varieties.