Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/20/2004
Publication Date: 6/20/2004
Citation: Burgos, N.R., Counce, P.A., Gealy, D.R., Norman, R.J., Shivrain, V.K., Stiers, E.N. 2004. Some physiologtical and competitive advantages of red rice over rice [abstract]. In: Proceedings of 4th International Weed Congress, Durban, South Africa. p. 75. Interpretive Summary:
Technical Abstract: In the southern U.S. and other rice-producing countries, red rice (Oryza sativa) is a troublesome weed in rice production. Red rice is highly competitive, reduces harvesting efficiency, and contaminates harvested grain with red kernels. Red rice problem spurs the herbicide-resistant rice (ClearfieldÒ, Liberty LinkÒ) technology. To improve management strategies for red rice, we need to know crucial biological and physiological differences between it and cultivated rice. Experiments were conducted at Stuttgart and Fayetteville, AR, USA between 1999 and 2003 to gain more understanding of the biology and physiology of red rice. For a self-pollinated plant, red rice has extraordinary phenotypic diversity. In Arkansas (rice area ~ 0.6 million ha), two major types of red rice exist - strawhull and blackhull. Strawhull types are 84 to 180 cm tall, produce 24 to 193 tillers, and flower at 11 to 19 weeks after planting (WAP). Blackhull types are 76 to 196 cm tall, produce 12 to 194 tillers, and flower at 11 to 18 WAP. Some biotypes are as short as cultivated rice. Canopy structure differed. Red rice photosynthesized at a higher rate and adapted to shade better than rice. Carbon isotope discrimination analysis did not indicate that red rice evolved an intermediate C3 pathway. In non-competitive conditions, red rice produced more tillers and biomass than rice. Seedling red rice had more root growth than rice 21 d after seeding. In competitive conditions, red rice responds more to nitrogen and takes up more nitrogen than rice.