Development of fine-leaved Festuca grass populations identified genetic resources having potential for improved forage production and wildfire control in the western United States

Authors: Robbins, Matthew; Staub, Jack; Bushman, Shaun

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2016
Publication Date: 6/1/2016
Citation: Robbins, M.D., Staub, J.E., Bushman, B.S. 2016. Development of fine-leaved Festuca grass populations identified genetic resources having potential for improved forage production and wildfire control in the western United States. Euphytica. doi: 10.1007/s10681-016-1644-z.

Interpretive Summary: The semi-arid and arid rangelands and irrigated pastures of the western U.S. provide a broad array of ecosystem services, including livestock forage, a diversity of native plants, pollinators, animals, and recreational activities. However, disturbances by wildfire, livestock, wildlife, and humans (including recreational activites) have contributed to degraded conditions on much of America's 800 million acres of rangeland. The Great Basin area of the western U.S. is, in fact, classified as one of the most ecologically endangered regions in the North America. Increased wildfire frequency, intensity and unpredictability in the wetern U.S. is due to the prevasive cyclic accumulation and burning of invasive annual plant species that compete with and displace native perennial rangeland species. Thus, many plant improvement efforts in semi-arid regions of the Great Basin in the western U.S. focus on developing plant materials that provide novel germplasm to revegetate disturbed areas, increase forage quality, improve wildlife habitat, and reduce undesirable weed invasion and associated wildfire frequency. Fire-resilient grass vegetation that improves forage production and reduces wildfire spread, however, has been difficult to identify given their specific adaptations, lack of late maturity (i.e., summer greening), and often poor stand establishment and persistence. Although some fine-leaved fescue species possess abiotic stress tolerance and remain green throughout the growing season, many of these have not been rigorously evaluated for their potential use in greenstrips in the western U.S. Therefore, a study was designed to evaluate a broad array of fine-leaved fescue species, select and hybridize high performance individuals, then evaluate these hybrid populations for their potential as a forage contributor and fire control under Great Basin desert conditions. Sixty-four geographically diverse (U.S., Middle Eastern, North African, and Asian sources) fine fescue accessions of 11 species were evaluated in a field nursery in North Logan, UT, to identify and improve grasses for use in greenstrips in U.S. western rangelands. Eighteen individuals were identified, hybridized (mated in pair combinations), and then tested at three locations in the Great Basin. Four hybrid populations were identified which, when compared with commonly used cultivars, were dramatically better in plant vigor, color, biomass yield, regrowth after clipping, and seed production. These populations will be useful to plant breeders for improvement of rangeland fine leaved grasses for western U.S. rangelands to increase rangeland productivity and sustainability.

Technical Abstract: Drought and heat tolerant fine-leaved fescue (Festuca ssp.) grasses have potential as components in rangeland greenstrips for wildfire control in semi-arid climates. However, such fine-leaved grasses have been difficult to identify because of specific adaptations, lack of late maturity, and often poor stand establishment and persistence under rangeland conditions. Therefore, between 2008-2010, 64 geographically diverse (U.S., Middle Eastern, North African, and Asian sources) fine fescue accessions of 11 species were evaluated in a field nursery in North Logan, UT, to identify and improve grasses for use in greenstrips in U.S. western rangelands. These plant materials were visually evaluated for relative plant vigor, color, and biomass, and in 2009, the best performing 18 single-plants [F. ovina L. (1) F. valesiaca Schleich ex. Gaudin (5), F. valesiaca Schleich ex. Gaudin subsp. valesiaca (4), F. valesiaca Schleich ex. Gaudin subsp. pseudodalmitica (3), F. heterohylla Lam. (1), F. brachyphylla Schult. ex Schult. & Schult. f. (2), F. filiformis Pourr. (1), and F. lenensis Drobow (1)] were selected for plant improvement. Controlled bi-parental matings among these selections (2010) produced 18 paired-cross progeny (populations) that were planted in 2011 and evaluated along with 5 commercial F. ovina (2), F. trachyphylla (1), and F. rubra L. ssp. rubra (1), and F. rubra L. ssp. commutata Marker-Dann (1) checks in replicated trials in 2012-2013 at Malta, ID, Blue Creek, UT, and North Logan, UT, where mean annual location precipitation is 200 mm, 350 mm, and 450 mm, respectively. Plants were evaluated for color (spring green-up), relative vigor, biomass, seed yield, persistence, and regrowth over two years (2012-2013). When considering all traits over both years and locations, four populations (R4S4, R4S6, R4S22, and R4S32) with parents originating from Turkey (F. ovina), Russia (F. valesiaca), Iran (F. ovina), and the U.S. (F. ovina) performed equal to or better than 'Durar' (the best performing commercial check) or 'Covar' depending on test location. In the harshest (lowest precipitation) environment (Malta, ID) the average performance of these four populations compared to 'Durar' was 84-210% for vigor, 79-90% for color, 65-562% for biomass, 64-296% for seed yield, 92-117% for persistence, and 164-454% for regrowth, where R4S22 demonstrated the best performance. Data indicate that these populations or progeny derived from them may be more suitable than 'Covar' and 'Durar' for forage production and as components in greenstrips on arid U.S. western rangelands.