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

Abstract

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 progeny 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 progeny seed responses to determine the sensitivity window to the maternal temperature effects in controlled and field environments. We observed that the occurrence of hot temperatures during the late reproductive stage affected weedy rice dormancy. For this effect to influence progeny seed germination, mother plants had to experience two weeks of hot treatment, especially on weeks 4 and 5 after flowering, resulting in a delay on dormancy release after seed after-ripening. 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. Altogether, our results indicate that the timing and duration of the maternal environment fluctuation may serve as an input to better predict weedy rice seed responses and develop targeted and more precise control programs. HighlightTwo weeks of maternal heat in the late reproductive stage are critical for delaying the release of dormancy in weedy rice seeds, which can affect plant fitness and control strategies.