Drying and storage effects on germination of primed grass seeds

Abstract

Cheatgrass (Bromus tectorum L.) has become the dominant species over large areas of rangeland in the Great Basin region of the western United States. Rapid germination at low temperature may contribute to the competitive success of cheatgrass in areas formerly dominated by native sagebrush and bunchgrass species. The objectives of this study were to determine whether seed priming could be used to stimulate low-temperature germination rate of native bunchgrass seeds and whether any priming effect was retained after drying and storage. Matric-priming was used to enhance germination rate response of 7 Great Basin native perennial grasses: thickspike wheatgrass [Agropyron dasystachyum (Hook.) Scribn.], bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Love], canby bluegrass (Poa canbyi Scribn.), sandberg bluegrass (Poa sandbergii Vasey.), bottlebrush squirreltail [Sitanion hystrix (Nutt.) J.G. Smith], sheep fescue (Festuca ovina L.), and basin wildrye [Leymus cinereus (Scribn. and Merr.) A. Love]. Priming enhanced germination rate of these species by 4 to 8 days at 10 degrees C. All species except canby bluegrass and basin wildrye could be induced to germinate as quickly as cheatgrass if they were not air-dried after priming. All species except canby bluegrass retained significant germination enhancement after 11 weeks of storage but only bluebunch wheatgrass maintained a germination rate comparable to cheatgrass when seeds were dried for storage.