Comparison of emergence speed and sterility in two sterile annual hybrid cereal grasses developed for use in restoration

            Two varieties of sterile annual hybrid (SAH) cereal grasses (Triticum aestivum x Elymus repens and Triticum sp. x 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.  Secondly, we investigated whether the SAH grasses were indeed sterile.  Seeds of both SAH varieties were germinated in a growth chamber along with B. tectorum and four native 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.  T. aestivum x E.  repens consistently germinated fastest under all moisture and temperature levels, followed by Triticum sp. x Secale sp., then B. tectorum and, finally, the four native species.  The sterility trial indicated that, while seed production for both SAH varieties was highly variable among individuals, all seed 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.