Nitrogen Use Efficiency (NUE) and Malt Quality GWAS in Elite Facultative/Winter 6-Rowed Barley (Hordeum vulgare)

Improving crop nitrogen use efficiency potential improves crop sustainability - whether sustainability is defined in terms of economics, land stewardship, or success in the face of climate change. To this end, the Triticeae Coordinated Agricultural Project (TCAP) was created to develop wheat and barley varieties adapted to more variable temperatures and reduced inputs. As part of the TCAP, this project focuses on identifying alleles for nitrogen use efficiency (NUE) and malt quality in facultative/winter 6-rowed barley (Hordeum vulgare). To identify NUE loci, we tested a GWAS panel of 300 elite lines for performance under standard nitrogen (N) and reduced N (70% of standard) treatments, in two years and two locations (Corvallis, OR and Logan, UT), all fall-planted, with the Logah, UT site irrigated. In total, we rated 7 agronomic traits and 4 yield component traits. Canopy spectral reflectance was used as a higher-throughput proxy for plant nitrogen status. Malt quality was assessed in both years with grain from the standard N treatment at the Corvallis, OR location. Genotypic data for GWAS were obtained by a 9,000 marker SNP assay. Preliminary analysis showed significant genotypic variation for NUE indices in 6 agronomic traits, including yield (α=0.001 for all 6 traits). Genotypic variation was significant for 6 malt quality traits (α=0.01). GWAS results will be presented.