Rice Cultivar Production and Seed Overwinter Potential in Upstate Missouri

Climate change and opportunities for pharmaceutical rice (Oryza sativa L.) production in the U.S. may affect future production opportunities. Field research in 2005–2007 at Bethel (39º56'N, 92º3'W) and in 2005 at Novelty (40º01'N, 92º11'W) evaluated the production potential of rice cultivars (10 conventional or hybrid varieties), overwinter seed survival, and the effects of weeds on yield in upstate Missouri. Grain yields ranged from 3,880 kg ha-1 (Ilpumbyeo) to 10,540 kg ha-1 (Trenase). M103, M202 and XP723 yielded similarly to Trenase. Late-maturing cultivars had the greatest risk of yield loss due to frost damage. Weed interference [barnyard grass (Echinochloa crus-galli L.), fall panicum (Panicum dichotomiflorum Michx.), giant foxtail (Setaria faberi Herrm.), common cocklebur (Xanthium strumarium L.), and common waterhemp (Amaranthus rudis Sauer)] reduced grain yields of Cocodrie 35%, emergence by 4%, plant height by 21%, and head number by 21%. In fall 2005 and 2006, rice seed produced during the previous year was seeded on the soil surface, with vertebrate exclusion, and vertebrate plus invertebrate exclusion. Viable seed overwintered with 0.06 to more than 12% emergence the following spring. The yield potential of rice in upstate Missouri looks promising, but correct cultivar selection and weed control are essential for successful production.