Agronomic and genetic assessment of terminal drought tolerance in two-row spring barley

Authors: Gordon, Tyler; WANG, RUI - University Of Idaho; BOWMAN, BRIAN - University Of Idaho; KLASSEN, NATALIE - University Of Idaho; WHEELER, JUSTIN - University Of Idaho; Bonman, John; Bockelman, Harold; CHEN, JIANLI - University Of Idaho

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2019
Publication Date: 5/22/2020
Citation: Gordon, T.C., Wang, R., Bowman, B., Klassen, N., Wheeler, J., Bonman, J.M., Bockelman, H.E., Chen, J. 2020. Agronomic and genetic assessment of terminal drought tolerance in two-row spring barley. Crop Science. 60(3):1415-1427. https://doi.org/10.1002/csc2.20040.
DOI: https://doi.org/10.1002/csc2.20040

Interpretive Summary: Barley is one of the most widely grown cereal crops globally and is used for animal feed, malting and human consumption. Drought tolerance is an important trait for current and future barley production. In this study we evaluated 480 spring habit, two-row barley accessions from the National Small Grains Collection (NSGC) under irrigated and terminal drought conditions in small plots in 2014 and 2017. Agronomic traits including grain yield, test weight, protein content, thousand kernel weight, and kernel size were measured for each accession in both treatments and years. Forty accessions were identified that had stable high yield, high test weights, and low protein content across treatments and years. Many of these treatment-stable accessions were developed at North Dakota State University or collected from central Asia. Molecular markers from across the barley genome were used to conduct a genome-wide association study to identify genetic regions associated with trait stability across treatments. Chromosomes 2H, 3H, 6H and 7H contained markers that were significantly associated with test weight, and chromosomes 1H, 3H and 5H had regions that were significantly associated with protein content across treatments. Accessions and molecular markers significantly associated with agronomic trait stability across terminal drought and irrigated environments can assist with the development of drought tolerant barley.

Technical Abstract: Barley, Hordeum vulgare L., ranks fourth in global cereal grain production and is an important crop for animal feed, malting and human consumption. Identification of two-row barley germplasm with drought tolerance can increase genetic diversity of two-row barley germplasm and facilitate future barley breeding efforts. The present study evaluated 480 two-row spring barley accessions from the USDA National Small Grains Collection (NSGC) across two years of irrigated and terminal drought trials for grain yield, test weight, protein content, thousand kernel weight, and kernel size. Forty accessions were identified that showed stable high yield, high test weights, and low protein content across trials. Twenty of these accessions were cultivars or breeding lines originating primarily from North Dakota, and the other twenty accessions were landraces originating primarily from central Asia. Genome-wide association mapping revealed 15 drought-stable genetic loci significantly (FDR-adjusted P < 0.05) associated with at least one agronomic trait across and within treatments. One locus, on chromosome 2H between 27.2 and 29.8 Mbp was significantly associated with heading date, plant height, and kernel size across treatments in this study and heading date and the PPD-H1 mutation in a previous study. Genetic loci on chromosomes 2H, 3H, 6H and 7H were significantly associated with test weight, and loci on chromosomes 1H, 3H and 5H were significantly associated with protein content across treatments. Accessions and SNP markers significantly associated with agronomic trait stability across terminal drought and irrigated environments can assist development of drought tolerant barley germplasm.