1. Departamento de Matemática del Instituto Nacional de Ciencias Agrícolas La Habana; Carretera Tapaste, Km 3 1/2 San José de Las Lajas Apdo. Postal 32700 Habana Cuba
2. Biometrics and Statistics Unit of the Crop Research Informatics Lab (CRIL); International Maize and Wheat Improvement Center (CIMMYT); Apdo. Postal 6-641 Mexico D.F. Mexico
3. Dep. of Genetics and Plant Breeding; Institute of Agricultural Sciences; Banaras Hindu Univ.; Varanasi 221 005 India
4. CIMMYT South Asia Regional Office; P.O. Box 5186 Kathmandu Nepal
5. Dep. of Plant and Soil Sciences and Dep. of Statistics; Univ. of Kentucky; Lexington KY 40546-0312