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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVED PLANT GENETIC RESOURCES FOR PASTURES AND RANGELANDS IN THE TEMPERATE SEMIARID REGIONS OF THE WESTERN U.S.

Location: Forage and Range Research

Title: Identification of Species, Quantitative Trait Loci (QTLs), and Hybrids Important for Low-Input Biomass Production and Hetersis in Semiarid Cold-Growing Environments

Authors
item Larson, Steven
item Jensen, Kevin
item Robins, Joseph

Submitted to: International Symposium on Forage, Turfgrass and Biofuel Germplasm Research
Publication Type: Proceedings
Publication Acceptance Date: October 9, 2010
Publication Date: October 13, 2010
Citation: Larson, S.R., Jensen, K.B., Robins, J.G. 2010. Identification of Species, Quantitative Trait Loci (QTLs), and Hybrids Important for Low-Input Biomass Production and Hetersis in Semiarid Cold-Growing Environments. Proceedings of the International Symposium on Forage, Turfgrass and Biofuel Germplasm Research, pgs. 117-120, October 9-13, 2010. Yangling, China.

Interpretive Summary: In recent years, there has been a great deal of interest in utilizing semiarid cold-growing regions of western North America as a source to produce large-statured perennial grasses as a cost-effective source of either forage production or use as biofuels. These environments present some unusually harsh growing environments and the ability to maintain stable sources of forage production can be difficult. This study looks at native and introduced cool- and warm-season grasses to identify species with superior forage production. First-year (2008) biomass harvests were taken on July 25 at Hyde Park, UT, and July 29 at Tetonia, ID. Second-year (2009) biomass harvests were taken on August 10 and 11 at Hyde Park, UT, and August 4 at Tetonia, ID. Tall wheatgrass had significantly higher forage yields than all other species tested in the first year, but the basin wildrye and Altai wildrye, and the creeping x basin wildrye hybrids displayed large gains in biomass production in the second-harvest year. Results of this study show that most large-statured cool-season grasses perform better than warm-season switchgrass, at these testing locations. The study also identified genetic markers for biomass production.

Technical Abstract: Interspecific hybrids of tall caespitose Leymus cinereus (Scribn. & Merr.) A. Love and strongly rhizomatous Leymus triticoides (Buckley) Pilg. display a heterotic combination of traits important for perennial grass biomass production. The objectives of this study were to: 1) compare seasonal biomass accumulation among Leymus wildrye species and hybrids relative to other large-statured perennial grasses, and 2) identify genes, QTLs, and traits associated with biomass accumulation and heterosis in full-sib mapping populations derived from two L. triticoides x L. cinereus hybrids backcrossed to one L. triticoides parent plant, under low-input management at two locations in semiarid cold-growing environments. Second-year biomass means (Mg/ha plus or minus SE) varied among key reference species including festuca arundinaceae Schreb. (2.1 plus or minus 0.4), L. triticoides (2.6 plus or minus 0.4), Panicum virgatum L. (3.6 plus or minus 0.6), Leymus angustus (Trin.) Pilg. (6.38 plus or minus 1.0), L. cinereus (7.2 plus or minus 0.4), Thinopyrum intermedium (Host) Barkworth & D.R. Dewey (8.3 plus or minus 0.9) and Thinopyrum ponticum (Podp.) Z.-W. Liu & R.-C. Wang (8.7 plus or minus 0.9). T. ponticum was significantly better than all other species tested in the first year, but L. cinereus, L. angustus, and Leymus hybrids showed the greatest second-year gains. The second-year yields of the Leymus hybrids ranged from 5.5 to 7.6 (Mg ha-1) were equal to or significantly greater than the L. cinereus Acc636 parent (5.9 plus or minus 0.7) and much greater than the L. triticoides Lt-F03 parent genotype (1.4 plus or minus 0.6). Significant QTLs were detected in the first two harvest years for both populations. The chromosome position of biomass QTLs were generally stable over years and locations, and showed correspondence with plant height, culm width, flowering, protein, and fiber QTLs. However, the location of biomass QTLs did not correspond between the TTC1 and TTC2 families.

Last Modified: 9/20/2014