1. Universidade Federal Mato Grosso, Faculdade de Agronomia, Cuiabá, MT 78060–900, Brazil
2. CNPAB/EMBRAPA, Seropédica, Itaguai, RJ 23851–970, Brazil
3. Plant Science Laboratories, Sir Harold Mitchell Building, University of St Andrews, Fife KY16 9AL, UK
4. CPAP/EMBRAPA, Corumbá, MS 79300–900, Brazil