Developmental Rates of Wild Oats (Avena fatua) and Wheat (Triticum aestivum)

Prediction of the developmental stages of wheat and wild oats would be useful in order to: 1) correctly time the application of herbicides, and 2) accurately schedule research and cultural operations. The Haun developmental scale which numbers leaf development and describes floral development on the main stem of grasses was found to be suitable for describing the development of semidwarf wheat and wild oats in California. Haun developmental rates of wheat and wild oats were similar. Interference by wheat or wild oats in mixed cultures did not change the developmental rate of either species when grown with added nutrients and water. Degree days gave better correlations with development than calendar days when different planting dates, years, and locations were compared. A degree day model with a 5 C base temperature and a second-order polynomial expression gave accurate predictions of developmental stage, which correlated well with field data.