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Keywords:

  • competition;
  • germination speed;
  • Great Basin grasses;
  • moisture stress;
  • temperature stress;
  • restoration

Abstract

Two varieties of sterile annual hybrid (SAH) cereal grasses (Triticum aestivum×Elytrigia elongata and Triticum sp. ×Secale sp.) have been developed as tools for restoration to circumvent problems associated with the use of exotic perennial grasses in wildlands. Recent research has shown that both varieties of SAH grasses performed better than native species when sown into Cheatgrass (Bromus tectorum)-dominated rangelands. The primary goal of this study was to see whether early emergence was a potential mechanism contributing to the success of SAH grasses. Second, we investigated whether the SAH grasses were indeed sterile. Seeds of both SAH varieties were germinated in growth chambers along with B. tectorum and four perennial grasses. Seeds were exposed to three moisture levels and four temperature regimes. In a separate experiment, seed from 10 individuals of each SAH variety grown in a greenhouse were tested for sterility. Triticum aestivum×E. elongata consistently emerged fastest under all moisture and temperature levels, followed by Triticum sp. ×Secale sp., then B. tectorum, and, finally, the four perennial grass species. All interactions also were significant; these interactions modified without negating the general patterns revealed in the main effects. Seed production in the sterility trial for both SAH varieties was highly variable among individuals and all seed that were produced germinated. The ability of SAH grasses to maintain rapid emergence under adverse conditions suggests that they may be a useful tool in restoration; however, their lack of true sterility may contradict the goals of land managers.