1. Department of Agronomic and Forestry Sciences, Plant Science Center, Universidade Federal Rural do Semi-Árido—UFERSA, Av. Francisco Mota, 572, Costa e Silva, P.O. Box 137, Mossoró 59625-900, RN, Brazil
2. Department of Plant and Agroecosystem Sciences, University of Wisconsin, Madison, 1575 Linden Dr., Madison, WI 53706, USA
3. Department of Agronomy, Universidade de Rio Verde, Rio Verde 75901-970, GO, Brazil