Location: Forage and Range Research2009 Annual Report
1a. Objectives (from AD-416)
Evaluate and develop new germplasm and cultivars with enhanced seed production, germination, seedling vigor, salinity tolerance, winter hardiness, drought tolerance, and forage yield and quality and verify their ability to improve the sustainability and productivity of rangelands and pastures in the semiarid western U.S. • Objective 1: Collect, characterize, and evaluate grass, legume, and forb germplasm for genetic variation, adaptation, establishment and forage characteristics for use on Western rangelands and the rangeland-urban interface. • Objective 2: Describe and identify useful traits for improved forages, using physiological, biochemical, and genomic techniques. • Objective 3: Identify breeding and selection strategies to make plant selection more effective. • Objective 4: Develop germplasm/pre-variety germplasm/cultivars of grasses, legumes, and forbs with improved seed production, seedling establishment, forage production, persistence, and drought tolerance on rangelands of the Western U.S. • Objective 5: Develop and evaluate new plant cultivars that are more tolerant of biotic and abiotic stresses, more competitive, more persistent, and easier to establish and maintain in irrigated pastures in the Intermountain West. • Objective 6: Identify functional differences between invasive weeds and improved plant materials and evaluate potential methods and improved plant materials to diversify crested wheatgrass communities.
1b. Approach (from AD-416)
Combine expertise of a research team of plant breeders, plant physiologists, ecologists, and molecular biologists to acquire, characterize, and breed native and introduced range, pasture, low-maintenance turf, and bioenergy plant materials. There is a need for additional plant materials for the conservation, restoration, renovation, and reclamation of range and forage lands, including irrigated pastures. New releases will provide improved plants needed to establish and maintain economically and environmentally sustainable pastures and rangelands in the semiarid regions of the Intermountain West. Identify new sources of genetic diversity for cultivar development. Describe establishment of grasses, legumes, and forbs characteristics such as ability to sustain high quality forage on disturbed sites under grazing pressure when competing with invasive weeds, and important physiological and biochemical mechanisms. Molecular and cytogenetic approaches will be used to identify and characterize genetic mechanisms to improve efficiency of genetic enhancement and plant breeding. The competitive ability of released plant materials will be enhanced for traits such as seed germination, seedling vigor, rhizome development, salinity tolerance, drought tolerance, and forage quality and yield. The new plant materials will be evaluated for their improved ability to perform key ecological functions, satisfying the diverse needs of our customers. Evaluate potential invasiveness of new plant germplasm.
3. Progress Report
Breeding efforts at the Forage and Range Research Laboratory (FRRL) to collect, characterize, evaluate, and develop improved plant materials for turf, pastures, and rangelands adapted to the western United States continues in native and introduced legumes (spreading alfalfa, prairie clovers, cicer milkvetch, Kura clover, sainfoin, birdsfoot trefoil, and Utah sweetvetch), forbs (globemallow, small burnet, and forge kochia), dryland range grasses (crested and Siberian wheatgrass (WG), bluebunch WG, thickspike WG, Snake River WG, western WG, Russian wildrye (WR), bottlebrush squirreltail, and slender wheatgrass), irrigated pasture grasses (tall fescue, orchardgrass, meadow brome, timothy, and creeping foxtail), and low-maintenance turf grasses (bluegrasses, fescues, and crested WG). Traits of interest include increased forage yield and quality (CP, NDF, IVTD, and lignin), seed yield, germination, establishment, drought tolerance (persistence), salinity tolerance, abiotic stresses, and turf quality. ‘Recovery’ western wheatgrass cultivar with increased seed germination and seedling establishment, Antelope Creek and Pleasant Valley bottle brush squirreltail germplasm have been released for use on dryland revegetation projects in the Central Great Plains and Great Basin regions of the U.S. Warm-season grasses were evaluated under a line-source irrigation study for their adaptation to the western U.S. and potential for biomass/biofuel production. Molecular genetics research continues to play a critical role in the plant evaluation and development programs at the FRRL. EST libraries were constructed for orchardgrass with SSR primers validated. Tested 1200 orchardgrass EST primer pairs on four tall fescue DNA samples, and began genotyping informative markers in tall fescue breeding sources. In Kentucky bluegrass, several hundred genes were sequenced with differential expression under salt stress. Genotyping of the Leymus mapping populations EST polymorphisms and wheat-Leymus chromosome addition lines was completed. EST-SSR markers for wild relatives to wheat in Thinopyrum bessarabicum, Th. elongatum, and Th. junceum were established using disomic alien addition lines of wheat. 1392 EST-SSR primer pairs have been screened for polymorphisms among parents and hybrids of the bluebunch wheatgrass mapping population. Thirty-five plant communities historically seeded with crested wheatgrass in the Great Basin were evaluated for soils, vegetation, and seed banks. Results from analyses indicate that these communities are resistant to invasive annual plant species while providing stability for soils and regeneration of big sagebrush. The invasive annual, cheatgrass, invests proportionately more in root length relative to shoot length than desirable native perennial grasses. Seedlings of bluebunch wheatgrass, a large-seeded species, invest primarily in biomass production, a slow-growth strategy. Seedlings of Snake River wheatgrass, a small-seeded species, invest primarily in root and leaf surface area, a fast-growth strategy enhancing its ability to compete with annual invasive grasses.
1. Techniques for using new herbicide for rangeland invasive weeds outlined: Invasive brome species (Bromus spp) compromise rangeland productivity and ecosystem integrity throughout California grasslands, the Great Basin, the Snake River Plain, and Mojave Desert ecosystems. Selective herbicides have only recently been available for control of these invasive grasses. The Forage and Range Research Lab completed a 3-year study on the implications of using the herbicide imazapic. ARS scientists clarify specifics of how to achieve ideal weed control without injuring species seeded to revegetate invaded areas. Their results showcase that in two rangeland plant communities, exceeding the 6 oz per acre herbicide rate can significantly hinder recently seeded desirable reclamation species, even though higher herbicide rates may improve invasive plant control. This study is particularly helpful to land owners and rangeland managers who can use this technology on big sagebrush and salt desert shrublands, two of the primary ecosystems invaded by cheatgrass (Bromus tectorum). Because few practical tools are available to control cheatgrass, this research is a major advancement toward the adoption of ecologically based integrated pest management strategies for rangelands.
2. Merits of warm-season grasses for biomass production in the Intermountain U.S: ARS scientists at Logan, UT investigated the merits of using warm-season grasses for biomass production under various irrigation levels for potential biomass/biofuel production. They conclusively showed that warm-season grasses produce substantially less biomass than cool-season grasses under irrigated conditions of the Intermountain U.S. Despite the great push to use warm-season grasses, such as switchgrass, for bioenergy throughout the U.S., this work clearly shows that the push to produce warm-season grasses under irrigated conditions of the Intermountain U.S. is unmerited. Efforts to develop biomass crops for this area should not focus on warm-season grasses. Cool-season grasses or forage legumes are better choices. This has substantial impact on regional and national bioenergy objectives in this region of the U.S.
3. Construction of grass genomic DNA library and isolation of the gene related to stem branching: The formation of tillers and/or rhizomes from underground stem branch meristems is a functionally important trait in cereals and perennial grasses. The maize barrenstalk1 and rice lax panicle orthogene was previously known to control the initiation of lateral branch meristems, but this gene was not previously found in cool-season cereals or grasses. ARS and Texas A&M scientists used bacterial artificial chromosomes (BACs) to develop a library containing more than 6 copies of the Leymus wildrye genome and sequence the lax-barrenstalk1 orthogene of cool-season grasses. Leymus BAC libraries developed at the FRRL were used to sequence and identify possible upstream and downstream regulatory elements based on conservation of DNA sequences among the maize, sorghum, rice, and Leymus lax-barrenstalk1 orthogenes. Results of this work facilitate modification and genetic control of tiller and rhizome proliferation in a variety of cereal and perennial grass species.
4. ‘Recovery’, a New Western Wheatgrass Cultivar with Improved Seedling Establishment on Rangelands: Western wheatgrass has low seed production and poor seedling vigor, limiting its use when quick establishment is needed to stabilize degraded rangelands. To address this problem, Recovery western wheatgrass was developed and jointly released by the USDA-ARS, the U.S. Army Corps of Engineers, and the USDA-NRCS for its superior and faster seedling establishment under rangeland conditions as compared to other commercially available cultivars. Recovery was developed and tested over a period of 10 years for reseeding rangelands following severe disturbance, frequent wildfires, and soil erosion. The rapid, successful establishment (20% more successful than traditional cultivars) of Recovery allows land managers to use a native grass species to help limit weed infestation and soil erosion where the regularity of disturbances normally prevents western wheatgrass from becoming fully established. This new cultivar of western wheatgrass is being recommended by the USDA-NRCS and the U.S. Army Corps of Engineers for reseeding private, public, and military training lands throughout the northern Plains and Intermountain West.
5. New rapid and efficient test to distinguish seed contaminants in grass species: There are 16 mannagrass species (Glyceria spp.) in the U.S., three of which are introduced from Europe. Waxy mannagrass (Glyceria declinata) is one of those introduced European species, and has become invasive in the western U.S.A. Visually distinguishing the native North American mannagrasses from the European mannagrasses, especially waxy mannagrass, is impossible to do confidently. Mannagrass seeds also cannot be visually distinguished, such that unknown mannagrass seeds in annual ryegrass seed lots can prevent foreign export or even domestic export. Unknowingly, waxy mannagrass seed was used in vernal pool restoration in California rather than a native mannagrass, with the resulting waxy mannagrass invasion. Until recently there was no accurate test to identify which mannagrass species was present in seed lots. The FRRL in collaboration with the Oregon Department of Agriculture developed a quick DNA marker test that accurately distinguishes native North American from introduced mannagrass species. The method requires equipment that is present in most seed testing labs, and the paper publishing such research is currently under review by APHIS to become an official testing protocol.
6. Guidelines for use of a new subspecies of bottlebrush squirreltail for rangeland restoration in the northern Intermountain Region: Bottlebrush squirreltail (Elymus elymoides) has become widely used for rangeland restoration in the Intermountain Region since the release of the first plant materials of this species in 2005, but less is known about adaptation of specific plant materials of this highly genetically diverse grass species. Using DNA technology, ARS scientists in Logan, UT showed that one of bottlebrush squirreltail’s three major subspecies (subspecies brevifolius) should actually be divided into two subspecies, one centered in the Rocky Mountains that retains this name and a newly recognized subspecies centered in the northern Intermountain Region of Oregon and adjacent states. By comparing climatic data from plant collection sites with the respective plant genotypes and phenotypes from these sites, this research identified four geographic adaptive zones within which genetic material should be climatically adapted. Two plant materials, Antelope Creek Germplasm and Pleasant Valley Germplasm, are being released to satisfy the need for a seed source for two of these adaptive zones, in the western Blue Mountains of central Oregon and the eastern Blue Mountains of eastern Oregon and adjacent portions of Idaho and Washington, respectively.
5. Significant Activities that Support Special Target Populations
During 2009, the Forage and Range Research Lab conducted an outreach program that included speakers from FRRL and surrounding University Extension Specialists. At Fallen, NV, we were invited by an agricultural service company to be part of their Crop and Soil School. This program addressed the following subjects; pasture grasses and legumes, adaptation of rangeland plants (grasses, forbs, and legumes), when and how to plant rangelands, and seeding mixtures. It was taken to two locations: Powell, WY and Fallen, NV. Attendance at each meeting ranged from 45 to 60 and included ranchers, farmers, and public land agencies. Distributed at each program were handouts and the ‘Intermountain Planting Guide’. Given the response of the last three years to program surveys we will continue to go out each year.