1. Dep. of Genetics and Plant Breeding, Escola de Agronomia; Federal Univ. of Goiás; Campus Samambaia, Ave. Esperança, s/n CEP 74690-900 Goiânia Goiás Brazil
2. This article is dedicated in memoriam to O.P. Morais
3. Embrapa Arroz e Feijão; Rodovia GO-462, km 12, Rural Zone, CP 179 CEP 75375-000 Santo Antônio de Goiás Goiás Brazil