Dormancy Breaking and Germination Requirements of Nimble Will (Muhlenbergia Schreberi Gmel.) Seeds

Abstract

Nimble will (Muhlenbergia schreberi Gmel.), a native perennial C4 grass, is a serious weed in horse pastures in the Bluegrass Region of Kentucky. This study investigated the dormancy breaking and germination requirements of this species. Seeds mature in October, are dispersed mostly during autumn and winter, and germinate in spring. Seeds were dormant at maturity, but they became nondormant during (1) dry storage in the laboratory, (2) 99 days of incubation on moist sand at 35/20 degrees C, or (3) cold stratification. Germination percentages were higher in light than in darkness, and cold stratified seeds germinated to higher percentages than dry-stored seeds. Seeds sown in a nonheated greenhouse in autumn were cold stratified during winter, and they germinated in spring when temperatures became nonlimiting. However, seeds that remained on the parent plants in the field over winter did not gain the ability to germinate at spring temperatures (20/10 degrees C) by spring. Under some test conditions, the intact palea and lemma inhibited germination, but under other conditions they were not inhibitory.