Developing a Nested Association Mapping Population in Barley Utilizing the National Small Grains Core Collection

Elite barley germplasm in the U.S. is limited in genetic variation. The National Small Grains Core Collection (NSGCC) is a valuable but underutilized source of  novel alleles to improve disease resistance, nitrogen use efficiency, and other desirable traits. To exploit diversity in the NSGCC, a nested association mapping (NAM) population was created by crossing the elite common parent Rasmussen to 91 6-row accessions randomly sampled from the NSGCC. To assess the phenotypic variation that was captured by these 91 accessions, we examined data for agronomic, morphological, malting quality, disease, winter growth habit, and food related traits available in The Triticeae Toolbox (T3, triticeaetoolbox.org).  We compared the range and distribution of traits for all 1,313 six-rowed lines in the NSGCC to those of the 91 parent lines. These parent lines are representative of the entire collection for heading date, plant height, kernel weight, and reaction to spot blotch. Additionally, GPS visualization of the origin of the lines shows that the selected parents represent a broad geographic range of barley. Work in progress will assess over 6,000 SNP markers to compare the parents to the entire collection. Work so far indicates this barley NAM population should capture significant genetic variation present in the NSGCC and be a useful resource to conduct mapping for a wide variety of traits. The genetic information and germplasm resulting from this project will serve as a valuable resource to better exploit native genetic diversity in cultivated barley for plant breeding.