SummarySeven parents and 21 bulk hybrid populations of the F2 generation of a half-diallel cross of winged bean were grown in lowland Papua New Guinea in the dry season with irrigation. The mean yield of green pods was 1092 g m−2 over nine weeks of regular harvesting, and the best bulk hybrid population yielded 1782 g m−2. Both general and specific combining ability effects were significant for yield. The substantial deviations in yield of the F2 bulk hybrids from their mid-parent values demonstrated that hybrid yields were not predictable from parental values, and hence, that progeny testing for yield was necessary. In contrast, the performance of the parents in hybrid combination was largely predictable from the parents for the characters pod weight, length and width. Both general and specific combining ability effects were significant for time to flower, but the general combining abilities were strongly correlated to the parental means. There were no significant differences between the populations for ...