A Critical Window of Maternal Temperature Effects on Weedy Rice Seed Dormancy

Seed dormancy is a critical trait for the survival and adaptation of agricultural weeds. The maternal temperature after flowering influences the post-dispersal response of seeds, which adds layers of complexity to weed control management programs. Understanding when the maternal environment exerts its effect on seed dormancy provides valuable insights into plant fitness and weed management.

In this study, we investigated weedy rice seed responses to determine the sensitivity window to the maternal temperature effects in controlled and field environments.

We observed that the occurrence of high temperatures during the late reproductive stage affected weedy rice dormancy. For this effect to influence seed germination, mother plants had to experience two weeks of high temperature treatment, especially on weeks 4 and 5 after flowering, resulting in a delay on dormancy release. Early and late transplanting in the field, which exposed mother plants to different environments after flowering, showed delayed release from dormancy consistent with the sensitivity window and responses in controlled conditions.

Our results indicate that the timing and duration of the maternal environment fluctuation affect seed dormancy release and serves as an input to better predict weedy rice seed responses and develop targeted and more precise control programs.