Combining ability of tropical maize germplasm in West Africa. 1: Open-pollinated varieties

africa central africa centrale africa occidentale afrique centrale afrique occidentale aptitud combinatoria central africa combining ability crop yield descendance fitomejoramiento germoplasma germplasm hybridation hybride hybridization hybrids ibridazione ibridi miglioramento genetico vegetale plant breeding progenie progeny rendement des cultures rendimiento de cultivos variedades de alto rendimiento west africa zea mays