MORPHOLOGY OF SMOOTH BROMEGRASS AND IMPLICATIONS RELATED TO MANAGEMENT AND POTENTIAL CONTROL

Smooth bromegrass (Bromus inermis Leyss.) is a sod-forming cool-season grass native to Europe and Asia. It was introduced to North America in the 1880s and occurs in all 50 contiguous states other than Florida and Alabama and all provinces of Canada. It is widely used for forage, conservation, and erosion control in temperate climates worldwide. Although its value as a forage crop is undisputable, it also may be invasive in native grasslands in the northern Great Plains. The objective of this study was to describe the proaxis of smooth bromegrass in terms of tiller origins from axillary buds at proaxial nodes, number of buds per proaxis, and frequency of buds that produce intravaginal and extravaginal tillers and compare these traits with the same in meadow bromegrass (Bromus riparius), a bunchgrass that is receiving considerable attention as a forage crop in the northern Great Plains. Post-anthesis reproductive tillers of each species were collected from replicated plots at Brookings, SD, during August and September. Proaxes of both species contained from 10 nodes per proaxis. In general, the frequency of proaxial buds that produced tillers was between 25 and 50% for both species. Harvesting the two species seven times over a period of 5 years resulted in a reduction in vigor for both species, but tiller density and biomass more negatively impacted for smooth bromegrass compared with meadow bromegrass.