Location: Small Grains and Potato Germplasm Research
2019 Annual Report
Objectives
This project intends to produce improved barley and oat germplasm, and new information and techniques to facilitate increased efficiencies. The objectives below will be the specific focus for the next five years:
Objective 1: Develop barley and oat germplasm with increased yield, better quality, and superior or novel resistances to biotic and abiotic stresses.
• Subobjective 1A: Develop low protein barley lines suitable for all-malt brewing.
• Subobjective 1B: Develop improved winter food barley varieties.
• Subobjective 1C: Develop facultative malting barley.
• Subobjective 1D: Develop barley varieties with improved Fusarium head blight resistance.
Objective 2: Translate new, sequence-based information into breeder-friendly tools for crop improvement in barley and oats.
• Subobjective 2A: Map Fusarium head blight (FHB) resistance and develop germplasm resistant to multiple diseases via marker-assisted selection.
• Subobjective 2B: Map quantitative trait loci (QTL) from new sources of adult plant resistance to oat crown rust disease (OCR) and develop milling oat germplasm resistant to crown rust.
Objective 3: Develop and implement novel biotechnological tools to produce barley germplasm with unique traits and enhance understanding of the genetic mechanisms underlying key traits.
Subobjective 3A: Deliver a site-specific recombination (TAG) platform via Ds-mediated transposition, and demonstrate functionality for RMCE in barley.
• Subobjective 3B: Construct and deliver Ds-bordered RNAi constructs that are transposition competent and that confer resistance to Fusarium head blight.
• Subobjective 3C: Perform genetic analyses of seed total phosphorus and phytic acid in barley.
Approach
Objective 1: Productive varieties will be developed that are improved for agronomic performance, protein and beta-glucan contents, winter survival, and Fusarium head blight (FHB) resistance. Hybridization with generation advance in greenhouses, New Zealand, and by doubled haploids will be used for population development. Breeding efficiency will be enhanced by investigating the genetics of key traits to enable genomic selection and the development of novel selection schemes. Agronomic performance and FHB resistance will be assessed in multi-location field trials. Grain quality will be assessed by physical examination and chemical analysis of grain for malt quality, protein and beta-glucan contents, and mycotoxin content.
Objective 2: Research will relate genetic sequence to disease resistance. Incorporating resistance to diseases that constrain oat and barley production outside of the Intermountain West will make Aberdeen germplasm more valuable. Since Idaho locations have low disease, direct selection for resistance is difficult. Indirect selection of sequence-based markers associated with resistance will combine good agronomic performance and grain quality with resistance to rusts and blotches. For diseases with established markers, development of new lines with specific markers will precede field screening in disease-prone sites outside of Idaho and in greenhouses using artificial inoculation. For other diseases, such as oat crown rust, screening in disease-prone sites will measure disease in multiple test lines, and statistical associations between specific sequences and resistances will identify and “map” new markers. Hybridization, generation advance, and genotypic and phenotypic screens will establish new populations from which lines that have improvements in disease resistance, yield, and quality will be selected.
Objective 3: Research will develop tools for experimental genetic manipulations and knowledge of how phosphorus is stored in seeds. Phosphorus is a critical nutrient and a major water pollutant. The hypothesis that the gene lpa-M955 is responsible for reduced seed phosphorus will be investigated by investigating statistical associations between the gene and different levels of seed phosphorus as measured by chemical assays. The hypothesis that new mutations can be found that result in 25% less phosphorus but without negative impact on plant performance will be examined by finding low-phosphorus mutant seeds, and growing them and selecting healthy plants that will then be tested in greenhouses and fields. To facilitate future genetic engineering experiments to identify additional genes of importance, the hypothesis that causing test genes to “jump” (transpose) into specific locations will help answer genetic questions will be tested by attempts to move a test gene into a specially designed receiver site. To test the hypothesis that this process can be harnessed to produce a non-chemical method of controlling a fungus that produces toxins in crop seeds, transposition will deliver an antifungal gene, followed by greenhouse and growth chamber screening for the reduced ability of the fungus to grow and produce toxins.
Progress Report
Progress towards the development of improved malting germplasm and cultivars (Objective 1) continued, including the low-protein types favored by the all-malt sector and the development of facultative-habit lines. Plant scale tests for three winter-habit malting barley lines and three spring-habit malting barley lines were conducted for the third year, which reflected continued industry interest based on good malting and agronomic performance. One or more of these lines likely will be released as a variety based on upcoming industry feedback. Two new spring-habit lines merited industry pilot testing for malt quality: 10ARS191-3 and 11ARS162-4. Approximately 4,000 pounds of seed of each line were produced to facilitate this testing. To address the specific needs of the all-malt brewing industry, we worked with the Brewer’s Association to identify materials that have the best package of malting characteristics for their use. This work included screening elite lines for low protein content. Most of our lines had protein contents higher than desired, and new sources of the low protein trait were identified by screening lines from the National Small Grains Collection (NSGC) and using the top 20 lines as parents of new populations. The facultative growth habit, which enables either spring or fall planting, is another trait that is poorly represented in our elite germplasm. We identified sources of this trait among breeding lines from other breeding programs and introduced them into our breeding program through crosses to our elite malting lines.
Development of food barley (Objective 1) moved forward on several fronts. Industry interest in the recently-released spring-habit, hulled, high-beta-glucan variety ‘Kardia’ has increased. We promoted the adoption of this improved variety by sending performance data and seed to several new potential users, and one decided to use ‘Kardia’ to replace the older variety ‘Salute’ in their production. In addition, the just-released, spring-habit, hulless, high-beta-glucan variety ‘Goldenhart’ is now available to growers. This variety brings to market the highest combination of beta-glucan content and agronomic performance. It is well-suited to production on water-limited, non-irrigated sites in the Intermountain West.
To address the growing problem of Fusarium head blight (FHB) in the Intermountain West (Objective 1), screening for resistance has become routine and this work has identified useful levels of resistance among elite, high-performing breeding lines. As lines combining tolerance to FHB with suitable agronomic and quality performance are identified, they will be used as parents for continued advancement of breeding lines and/or released as varieties. Since the emergence of FHB in traditionally low-disease environments, industry concern has spurred additional investment in FHB research. Progress from this investment included the establishment of an additional screening nursery in Kimberly, Idaho, which doubles our testing capacity. This work was done in collaboration with the University of Idaho. In addition, a new molecular screening technique to estimate fungal mycotoxin contamination was developed and tested for the first time. This technique shows promise for estimating mycotoxin concentrations more rapidly and cheaply than existing techniques. Finally, five new mapping populations were advanced several generations towards the goal of recombinant inbred lines, and a sixth was developed to completion via doubled haploid production (in collaboration with Oregon State University and the U.S. Wheat and Barley Scab Initiative). These populations will be used to investigate the genetics of resistance to FHB and foliar diseases, the development of molecular markers useful for selection of resistant lines, and as sources of useful germplasm that will be integrated into the breeding program (Objective 2).
Progress on research designed to increase resistance to oat crown rust (Objective 2) included the identification of seven oat accessions from the NSGC as carriers of adult plant resistance to crown rust disease. These were collected from early varieties grown in the U.S. (CIav2272, and CIav3390), from landraces of Mediterranean or other European origin (PI140903, PI285583 and PI287296) and from an early cultivar and landrace of South American origin (CIav4706, and PI237090). This work was made possible by collaboration with university and ARS collaborators at several locations. The crown rust resistance within these accessions was placed in the context of resistance currently available to breeders in terms of both map location and uniqueness of resistance alleles. Five “lineages” of adult plant resistance to crown rust have been identified using pedigrees and the historical data in the Germplasm Resource Information Network system: lines that include the Aberdeen101 breeding line in their lineage (e.g. MN841801, and URS21) which may have derived resistance from the old South American cultivar La Estanzuela; lines with ancestry that includes selections from the Red Algerian landrace (e.g. Dal, and URS21); lines with ancestry that includes selections from the Red Rustproof landrace (e.g. Sylva, and Red Rustproof); lines derived from crosses with the cultivar Victoria (e.g. Dal, and Sylva); and lines derived from crosses with Ukraine (e.g. Ukraine Reselection). Examples from each of these five lineages have been selected for crossing, in addition to the seven lines identified through screening the NSGC. This will allow us to use comparative mapping approaches to identify shared and unique genetic loci.
Work on recombination mediated cassette exchange and transposition-competent RNAi constructs (Objective 3) continued. Additional plants were identified with potential “ideal” TAG-locus characteristics (that is, an isolated, single TAG locus in a homozygous state). Efforts to introduce an EXCH (exchange) vector and effect recombination were stymied by difficulties with the barley transformation process. These difficulties also have prevented regeneration of plants with RNAi constructs designed to defend against FHB-induced mycotoxin resistance. To address in-house resource limitations that contributed to slow progress, we have partnered with researchers at the University of Wisconsin, that specialize in crop transformation, in an agreement that gives us access to improved physical and human resources to speed this research towards completion.
Accomplishments
1. Release of ‘Goldenhart’ food barley cultivar. Beta-glucan fiber in cereal grains provides cardiovascular health benefits. Continuous improvement of high-beta-glucan barleys is necessary to sustain profitable production and commercial use. Goldenhart was released as a new food barley because it has beta-glucan content as high as previous cultivars but with higher yield. ARS researchers at Aberdeen, Idaho, developed Goldenhart and seed production is managed by the Idaho Foundation Seed Program. Industry is interested in this barley and in 2018 production was contracted on over 3,000 acres.
Review Publications
Yimer, B.A., Gordon, T.C., Bonman, J.M., Esvelt Klos, K.L. 2019. Development and validation of a quantitative PCR assay method of assessing relative resistance of oat (Avena sativa) to crown rust (Puccinia coronata f. sp. avenae). Plant Pathology. 68:669-677. https://doi.org/10.1111/ppa.12988.
Bonman, J.M., Bockelman, H.E., Hijmans, R.J., Hu, G., Esvelt Klos, K.L., Gironella, A.N. 2018. Evaluation of grain ß-glucan content in barley accessions from the USDA National Small Grains Collection. Crop Science. 59(2):659-666. https://doi.org/10.2135/cropsci2018.10.0606.
Yimer, B.A., Bonman, J.M., Esvelt Klos, K.L. 2018. Mapping of crown rust resistance gene Pc53 in oat (Avena sativa). PLoS One. 13:e0209105. https://doi.org/10.1371/journal.pone.0209105.
Mahalingam, R., Bregitzer, P.P. 2019. Impact on physiology and malting quality of barley exposed to heat, drought and their combination during different growth stages under controlled environment. Physiologia Plantarum. 165(2):277-289. https://doi.org/10.1111/ppl.12841
