Germination of downy brome from southern Kansas, central Oklahoma, and north Texas

Abstract

Mature downy brome (Bromus tectorum L.) seeds collected in Texas, Oklahoma, and Kansas in mid-June did not germinate at summer temperatures even when supplied with adequate moisture. The after-ripening of seeds for 3 months produces germination of 50% or more in most populations, as does subjecting fresh seeds to November temperature regimes. These results are similar to those reported for downy brome seeds from eastern Washington, central Idaho, and central California in which fresh seeds are dormant. They differ from those reported for seeds from Montana, northern California, northern and western Nevada, southern Idaho, and northern Utah in which fresh seeds germinate at high percentages. Dormancy of fresh seeds from the Southern Great Plains delays downy brome germination until the fall season at which time rainfall and other climatic conditions are more favorable for its survival.