AFTER-RIPENING IN FESTUCA-IDAHOENSIS SEEDS - ADAPTIVE DORMANCY AND IMPLICATIONS FOR RESTORATION

Festuca idahoensis (Idaho fescue) was a common native perennial bunchg rass in the sagebrush steppe of the western United States until the in troductions of domestic livestock and alien plants. Restoration of Ida ho fescue to degraded sites will likely involve reseeding, and one of the factors affecting reseeding success is germinability of the seeds employed. We investigated effects of after-ripening and storage temper ature on germinability of Idaho fescue seeds collected from a central Oregon site. Six months of after-ripening were required before maximum germination was obtained. Storage of dry seeds at either room tempera ture (20 degrees C) or at cooler, alternating temperatures (5/15 degre es C) did not alter the rate at which dormancy was lost. Storage at th e warmer temperature promoted rapid germination in seeds that had brok en dormancy. Seed longevity varied greatly from year to year. Seeds pr oduced in a very dry year had poorer germination and shorter longevity than seeds produced during a year with near normal precipitation. Bec ause seed dispersal occurs in late July and early August for Idaho fes cue in central Oregon, a six-month after-ripening requirement ensures that the greatest potential germination coincides with the spring peri od most likely to provide sufficient moisture for seedling establishme nt.