Evaluation of Heterotic Patterns among Caribbean and Tropical ✕ Temperate Maize Populations

The integration of tropical maize ( Zea mays L.) germplasm into template breeding programs has been difficult and slow. More information on performance of temperate ✕ tropical populations and their heterotic combinations is needed. This study was conducted to compare heterotic patterns among four populations. Two, a Caribbean flint and a Caribbean dent, are useful in the tropics and have potential for temperate areas; the other two are temperate ✕ tropical populations adapted to the tropics. The four populations, their diallel crosses and reciprocals, and a commercial hybrid check were grown in two locations in Puerto Rico during two winter‐season environments. The best heterotic combination among the four populations was between the Caribbean flint and dent. The best‐yielding population per se was the temperate ✕ tropical population of Reid (Group B) heterotic pattern. The Caribbean flint population had highly significant negative maternal effects for yield. Both reciprocal crosses of the temperate ✕ tropical populations were low yielding. The results indicated that, for temperature breeding programs, both Caribbean populations should be useful for improving Corn Belt maize.