Resumen
- Few of the world's maize (Zea mays L.) germplasm collections have been systematically evaluated in spite of the recognized necessity of broadening the germplasm base of this crop. Knowledge of new heterotic patterns and the breeding potential of maize collections stored in gene banks can contribute to a widening of the genetic base. The objectives of this study were to (i) evaluate the breeding potential eight tropical maize germplasms, and (ii) provide further information to clarify the relationships among them. Five Colombian landraces (‘Andaqui’, ‘Común’, ‘Costeñio’, ‘Puya’, and ‘Yucatán’) and three improved maize populations (‘Tuxpeñio‐1’, ‘Suwan‐1’, and ‘ETO’) were crossed in a diallel mating system. The parents and the 28 hybrids were evaluated in six environments for grain yield, days to 50% silking, prolificacy, and ear height. Cuitivar (additive) and heterotic effects were highly significant (P ≤ 0.01) for all traits except ear height. Significant (P ≤ 0.05) cultivar heterosis and specific heterotic effects were found for grain yield, with an average 10% high‐parent heterosis. Cultivar effects were positive for Suwan‐1 (0.86**) and Tuxpeño‐1 (0.62**) and negative for Andaqui (−0.42*) and Puya (−0.78**). The same materials showed significant cultivar heterotic effects (0.29**, 0.12*, −0.23″*, and −0.22**, respectively). Specific heterosis was found in crosses between Tuxpeñio‐1 and Común (0.44″*), Yucatán (0.35*), and Suwan‐1 (−0.67**). The best materials were improved populations, Suwan‐1, and Tuxpeñio‐1. The ETO population did not perform well per se or in hybrid combinations. Yucatán outyielded ETO and was a parent in two of the three highest yielding crosses. The hybrid Tuxpeñio‐1 × Yucatán showed the highest high‐parent heterosis value (25%**). Results generally agreed with the reported relationships among the parents and pointed to Yucatán as a potentially useful genetic resource for tropical maize breeding programs.