Forage yield estimates provide relevant information to manage and quantify ecosystem services in grasslands. We fitted and validated prediction models of forage yield for several prominent grasses used in restoration projects in semiarid areas. We used field forage harvests from three different sites in Northern Utah and Southern California, USA, in conjunction with multispectral, high-resolution UAV imagery. Different model structures were tested with simple models using a unique predictor, the forage volumetric 3D space, and more complex models, where RGB, red edge, and near-infrared spectral bands and associated vegetation indices were used as predictors. We found that for most dense canopy grasses, using a simple linear model structure could explain most (R² 0.7) of the variability of the response variable. This was not the case for sparse canopy grasses, where a full multispectral dataset and a non-parametric model approach (random forest) were required to obtain a maximum R² of 0.53. We developed transparent protocols to model forage yield where, in most circumstances, acceptable results could be obtained with affordable RGB sensors and UAV platforms. This is important as users can obtain rapid estimates with inexpensive sensors for most of the grasses included in this study.

Rangeland revegetation is necessary to stabilize disturbed sites and increase forage production, but frequently fails due to a variety of environmental and biotic factors. Plant breeding efforts in perennial cool-season grasses result in the development of potential cultivars that must be evaluated in multi-environment trials to determine their level of adaptation. This study evaluated 49 cultivars for stand frequency and dry matter yield over five years at five environments in the Intermountain and High Plains regions of the United States. The results were significant differences among the included cultivars for both traits across and within environments. Yet, there was also crossover genotype × environment interaction. Thus, highest performing cultivars were to some extent dependent on the environment. Hycrest II crested wheatgrass and Vavilov II Siberian wheatgrass possessed high stand frequency (>80 %) and dry matter yield (>800 kg·ha⁻¹) across environments and within environments except at the Eureka, UT environment where they possessed low stand frequency. These cultivars, and species, also possessed high productivity and stability for both traits. Thus, breeding efforts in the species resulted in widely adapted cultivars that may lack specific adaptation to some environments.

Native grasses are widely used in the Intermountain West for restoration and conservation of semi-arid rangelands negatively impacted by exotic weedy annuals and recurrent wildfire. Their utilization, however, is typically limited by low seed yields and poor establishment. To address this, Destination Germplasm Snake River wheatgrass (Elymus wawawaiensis J. Carlson & Barkworth [Poaceae]) was released by USDA ARS on 31 May 2023. Destination Germplasm was developed directly from ‘Discovery’, released in 2007, being selected for emergence from deep seeding in the greenhouse, which is a generally recognized technique to improve seedling vigor and spike numbers in the field. Establishment-year (2021) biomass of Destination Germplasm exceeded ‘Secar’ by 118.1% and Discovery by 51.3% at North Park Farm (Hyde Park, Utah). Across 2 seed-production years (2022–2023), Destination Germplasm biomass and seed yield exceeded Secar by 41.0% and 43.7%, respectively, and Discovery by 24.4% and 78.3%, respectively. Likewise, for seed mass, Destination Germplasm exceeded Secar by 25.5% and Discovery by 16.1%. When fall-seeded at Nephi, Utah, in 2022 on an equal seed-number basis, 2023 stand establishment was 65.8%, 34.0%, and 11.5% for Destination Germplasm, Discovery, and Secar, respectively. This calculates to a 93.5% and 66.6% increase in establishment for Destination Germplasm relative to Discovery when sown on an equal seed-number and an equal mass basis, respectively. A strong positive correlation (r² = 0.958) was found between seed mass at North Park and establishment percentage at Nephi. Destination Germplasm will facilitate improved establishment and seed-production success relative to its predecessors, Secar and Discovery.