Population Dynamics of Downy Brome

Abstract

We investigated the periodicity of germination, longevity of caryopses viability, and reproductive capacity of downy brome ( Bromus tectorum L.) populations in relation to chemical and mechanical fallow and fall tillage weed control treatments. The important factors in the dynamics of downy brome populations are: (a) large numbers of viable caryopses are carried from 1 year to the next in the litter and soil; (b) downy brome caryopsis production is density dependent; and (c) the simultaneous germination characteristics of freshly harvested downy brome caryopses can be conditioned environmentally to continuous germination.