1. a Department of Crop, Soil, and Environmental Sciences , University of Arkansas , 1366 W. Altheimer Drive, Fayetteville , AR , 72704 , U.S.A.
2. b Northeast Research and Extension Center , University of Arkansas , P.O. Box 48, Keiser , AR , 72351 , U.S.A.
3. c Department of Horticulture and Crop Science , OARDC , 1680 Madison Avenue, Wooster , OH , 44691 , U.S.A.