Upland Rice and Allelopathy

Abstract

Upland rice (Oryza sativa L.) is mainly grown in Asia, Africa and Latin America. Yield potential of upland rice is quite low and invariably this crop is subjected to many environmental stresses. Further, when upland rice is grown in monoculture for more than two to three years on the same land, allelopathy or autotoxicity is frequently reported. Allelopathy involves complex plant and plant chemical interactions. The level of phytotoxicity of allelochemicals is influenced by abiotic and biotic soil factors. Adopting suitable management strategies in crop rotation can reduce or eliminate allelochemicals phytotoxicity. Rice yields can be improved by growing rice in rotation with other crop species. Allelochemicals of rice can be used for control of weeds in this crop as well as other crops that are grown in rotation with rice. This review highlights that present knowledge of allelopathy in upland rice is inadequate and fragmentary, and therefore, more controlled and field studies are needed to understand and to reduce the detrimental effects of allelopathy in the upland rice production.

Keywords:

• Allelochemicals
• Weed control
• Crop rotation
• Resistant cultivars
• Nutrient supply
• Rice

Acknowledgments

The authors thank Dr. Donald T. Krizek, Plant Physiologist, USDA-ARS, Beltsville, MD, and Dr. Joyce G. Foster, Research Biochemist, USDA-ARS, Beaver, WV, for peer review and giving helpful comments and advice for this review.