Miller, Michael2019-08-272019-08-272019-08https://hdl.handle.net/11299/206481Net blotch (Pyrenophora teres f. teres) is a major disease of barley (Hordeum vulgare). Genetic resistance in cultivated barley is mainly found in one major region of the genome, suggesting that wild relatives should be investigated to enhance the diversity of resistance in the cultivated species . This study looked at net blotch resistance in Hordeum jubatum, a member of the tertiary genepool of barley. Over 300 accessions of H. jubatum collected from 108 sites in central North America were grown in a greenhouse and tested for their reaction to pathotype Pt_1351 of P. teres f. teres. Twenty-eight differential accessions of barley were also evaluated as controls. Nine days after inoculation, plants were scored for their infection responses (IRs) on a ten-point scale. IRs were generally low, but variation was observed. The H. jubatum accessions had a mean IR of 2.9 and a range of 1 to 6.5. H. vulgare controls had mean IR of 2.5 and a range of 1 to 6. No general trend was seen with respect to IR and geographic location. The disease scores of the H. vulgare controls generally did not match expectations based on previous studies, but average infection scores similar to that of the H. jubatum in this study was seen in other studies of net blotch infection in wild Hordeum species. The lack of a trend in disease score compared to geographic location suggests that factors heavily influenced by geographic location, such as rainfall and barley cultivation, are not responsible for variation in net blotch resistance. Future studies of net blotch resistance in H. jubatum would benefit from increased replication to better assess differences between individual accessions. The variation in net blotch resistance seen in this study suggests H. jubatum may be a source of novel resistance and warrants further study into net blotch resistance in H. jubatum.enThesis or Dissertation