Location: Wheat, Sorghum and Forage Research
2018 Annual Report
Accomplishments
1. Asymmetry in synergistic interaction between Wheat streak mosaic virus and Triticum mosaic virus in wheat. Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are economically important viruses infecting wheat in the Great Plains region of the USA. WSMV and TriMV interact synergistically in co-infected wheat with dramatically increased disease severity and yield loss with elevated accumulation of both viruses. Since both of these viruses are transmitted by wheat curl mites, double infections in field-grown wheat are common, resulting in disease synergism. Understanding the underlying mechanisms of synergistic interaction between WSMV and TriMV would facilitate developing strategies to minimize losses from disease synergism. ARS scientists in Lincoln, Nebraska found that WSMV benefited from prior infection of wheat by TriMV during early stages of systemic infection while prior infection of wheat by WSMV negatively affected TriMV systemic infection. However, both viruses benefited from each other during late stages of synergistic interaction with acute symptom phenotype and increased accumulation of both interacting viruses. This study suggests that interactions between WSMV- and TriMV-encoded proteins enhance disease symptoms and suppress grain yield disruption of these interactions may prevent synergistic interactions between these viruses and help stabilize wheat grain yield under pathogen pressure.
2. Development and release of low phytic acid (LPA) germplasm. Low phytic acid mutants of wheat (Triticum aestivum L.) can reduce concentrations of this kernel anti-nutrient by one-third. The reduction of phytate increases the bioavailability and subsequently, the gut absorption of minerals in monogastric animals, including humans. ARS scientists at Lincoln, Nebraska developed novel breeding stockby mating of lines carrying a mutation (lpa-1) to Nebraska winter wheats. Multi-location grain yield testing, and selection for the low phytate (LPA) trait, resulted in the identification of eight LPA breeding lines adapted to the Great Plains of North America. The highest yielding LPA lines were not significantly different in grain yield from the adapted controls ‘Anton’ and ‘Intrada’, significantly higher in grain yield than ‘Big Sky’ and ‘Siouxland’, but significantly lower than the two highest yielding controls, ‘Freeman’ and ‘Ruth’. Overall, there were no significant differences in grain yield, grain volume weight, and grain protein concentration between the LPA lines and the mean values of the adapted controls. On average, the LPA lines had 18% more zinc than the adapted controls. Grain yield data obtained in diverse environments in Nebraska indicates no grain yield reduction associated with the low phytate trait, and shows the potential for development of high-yield cultivars with high mineral and low antinutrient concentrations. Eight LPA germplasm lines were released and deposited in the USDA-ARS National Small Grains collection for use by wheat breeding programs across the globe.
