2021 Volume 66 Issue 2 Pages 41-47
Winter cereal crops have been severely infested with wild oat (Avena fatua L.) in Ibaraki, Japan, especially in the western part of the prefecture. For effective use of soil-applied herbicides, seedling emergence of wild oat should be considered. In this study, using wild oat seeds collected from 10 populations in Ibaraki, we evaluated variation in seed dormancy using a germination test and a census of seedling emergence. We found four different types of seed dormancy among these populations: shallow (one population), medium (two populations), medium-deep (two populations), and deep dormancy (five populations). Most seedlings in the five populations falling under shallow, medium, and medium-deep dormancy types emerged by the end of December. In the five populations falling under deep dormancy, seedlings emerged throughout the growing season, from November to April. Following census of seedling emergence, it was found that medium-deep or deep dormancy populations had more viable seeds than shallow or medium dormancy populations, and that the highest seed viability was 57.0%. Ungerminated seeds could emerge the following year. In the production of winter cereals, it is considered that wild oat populations with deep seed dormancy are difficult to control using herbicides. In that case, multiple methods such as cultural control should be included.
