1. a Crop, Soil, and Environmental Sciences Department , University of Arkansas , 115 Plant Science Bldg, Fayetteville , AR , 72701 , U.S.A.
2. b Rice Research and Extension Center , University of Arkansas , P.O. Box 351, Stuttgart , AR , 72160 , U.S.A.
3. c Agricultural Statistics Laboratory , University of Arkansas , Fayetteville , AR , 72701 , U.S.A.