Variety x line cross - A suggested breeding procedure for maize in developing countries

Phra-Phutthabat No.5 (PB5), a widely grown local variety in Thailand, was crossed with open-pollinated varieties, S3 and S6 lines from different parts of the world. The resulting hybrids were tested in the dry season in Thailand, Laos and Israel with PB5 as the control. A number of hybrids were also tested in the wet season in Thailand and Laos. Hybrids giving significantly higher yields than PB5 were found in both the dry and the wet seasons. The variety x line crosses were superior to the variety x variety crosses at all locations. The hybrids with the South African germ plasm were intermediate, and those with the African and Asian germ plasm gave the lowest yields. The variety x line cross is suggested as a simple and rapid breeding procedure for the developing countries.