Genotype, environment and management effects on grain yield, milling quality, and nutritional density of oat in the Northern Great Plains

Milling markets and farmers demand grain characteristics that are consistent despite weather extremes. These characteristics may also be negatively correlated, such as between yield and nutritional value, thus imposing tradeoffs on managers and grain purchasers. This complicates variety selection and management. We examined the impacts of weather and management on oat ( Avena sativa L.) grain yield, milling quality, and nutritional content across three, commercially available, milling varieties, and characterized tradeoffs among these grain outcomes. Management contrasted three planting densities (targeting 225, 300, and 375 plants m −2 ) and two clover establishment practices (medium red clover ( Trifolium pratense L.) under-seeded with oats or no-clover fallow). Growing season cumulative precipitation ranged from 176 to 328 mm and average daily maximum temperatures from 23.0 to 25.9 °C. Cooler and wetter conditions generally supported higher yields and better milling quality, but at the cost of lower grain protein and β-glucan content. Average grain yield, test weight, protein content, and β-glucan content, and plump value across genotypes and treatments was 2906 kg ha −1 , 43.1 kg hl −1 , 4.72 %, 18.6 %, and 82.4 %, respectively. Variety selection and management could mitigate weather impacts and tradeoffs among grain characteristics. The semi-dwarf variety, Reins, excelled in favorable conditions, while medium-height Natty and Sumo tolerated drier conditions. Seeding rate also influenced grain nutrient content and milling quality, with higher stand densities resulting in higher test weight, protein, kernel plumpness depending on variety, and oil content depending on weather, but lower thousand kernel weight. Clover forage establishment, while rotationally beneficial, did not reduce grain yield, quality, or harvestability. Tradeoffs among grain yield and quality metrics across growing conditions were strong, yet variety-specific. Neither yield nor test weight were reliable indicators of milling quality or nutritional content. Therefore, breeders may further decouple grain quality traits to better meet the demands of the food oats market and improve weather resilience. Agronomists, meanwhile, may revisit target plant populations to improve grain quality while continuing to develop soil-building practices. • Variety, environment, and management alter oat yield, milling quality, and nutritional content. • Stand density influenced grain quality, nutrition, and agronomic traits. • Minimal impact of intercropped medium red clover on oat yield or quality. • Variety-specific tradeoffs among yield, milling quality, and nutrient content. • Variety selection and management may target specific markets and emphasize weather resilience.