Progress in Developing Weed-Suppressive Rice Cultivars for the Southern United States
For thousands of years, rice (Oryza sativa L.) has been among the most important crop species. Currently, it is the main food source for more than half of the earth’s population, with Asia producing and consuming about 90 percent of all rice (Singh and Khush, 2000). Approximately 596 million metric tons of rough rice is produced annually on 155 million ha worldwide (IRRI, 2002). In the United States 9.5 metric tons of rice are now harvested from about 1.3 million ha in two major regions: the southern Mississippi valley/Gulf Coast (Missouri ~6 percent of total ha; Arkansas ~49 percent; Mississippi ~8 percent; Louisiana ~17 percent; and Texas ~6 percent), and California (~14 percent) (NASS, 2002). The United States exports more than 40 percent of its rice production, ranking fourth in the world among rice exporters according to recent estimates (Childs and Burdett, 2000).