A comparison of the freezing tolerance of downy brome, Japanese brome and Norstar winter wheat

Abstract

The freezing tolerance of downy (Bromus tectorum L.) and Japanese (Bromus japonicus) brome were compared to Norstar winter wheat (Triticum aestivum L.) collected from similar sites. From December to April of 1987 downy brome was either equal to or superior in freezing tolerance to the winter wheat. Of the three species, Japanese brome was slightly less hardy in December but was of equal freezing tolerance in March and April. There was no correlation between freezing tolerance and tissue water content or tissue dry weight in the three species. These two bromes may become a serious weed in winter wheat because their cold hardiness is either equal or superior to our hardiest winter wheat cultivars. Key words: Downy brome, Japanese brome, winter wheat, freezing tolerance