Rice allelopathy - Where are we and how far can we get?

Widespread and increasing environmental concerns on herbicide use have worked as an eye-opener for alternative and new approaches for weed control. One of the new approaches is the attempt to utilize allelopathic potential in crops for weed suppression in the field. Allelopathy is the direct influence from one living plant on growth and development of another plant (Olofsdotter et al., 1995). As such, allelopathy research in rice has made remarkable progress in the last decade opening up for new possible strategies for weed control in nice. Allelopathic potential in growing rice was first found in a seed increase plot at Arkansas Rice Research Institute (Dilday et al., 1991). Since then, several groups all over the world have been working on screening rice cultivars for allelopathic potential, evaluated the possibilities for utilizing allelopathic features in rice for weed control, tried to find the allelochemicals responsible for allelopathic potential in rice, evaluated trade off effects from allelopathic potential in rice, and evaluated the possibilities for genetic improvements of rice cultivars to increase plant interference potential both from allelopathy and competition etc.. Weed science needs a paradigm shift where naturally occurring defense mechanisms against weeds are viewed as a possible strategy for weed management. With this paradigm shift we could create a breeding strategy for the future where cultivars are made "resistant" to one or several special weed problems.