Optimal temperature and light conditions for germination of Elymus glabriflorus

As of date, information regarding seed physiology and germination requirements of southeastern wildrye (Elymus glabriflorus (Vasey ex L.H. Dewey) Scribn. & C.R. Ball [Poaceae]) is limited. Five seed accessions were collected across a variety of habitats at different latitudes and were placed under a range of temperature and light regimes to determine optimal conditions for germination. Temperature treatments for germination included alternating day/night regimes from 10 to 25 °C in 5° increments. Light testing consisted of 4 treatments: constant light, constant dark, short day (8 h), and long day (16 h). Results from the temperature experiment indicated no correlation between latitude and temperature for optimal germination. The collection from the southernmost site, Laurel, Mississippi, and the northernmost site, Upton, Kentucky, had an optimal germination temperature of 20 °C. The short-day (8-h) treatment had the greatest initial germination (41% for 2010 and 61% for 2013). These results indicate that temperature requirements for germination of E. glabriflorus seed range from 15 to 20 °C and that shortening day length (< 16 h) is optimum.