Gene effects controlling the earliness in Flint-Maize.

The objetive of this investigation was to determine the inheritance of earliness in crosses between an early variety of maize called Gaspé and orange flint inbred lines from Argentina. The information obtained will be applied in breeding programs to select early materials. Inbreeds, with a long cycle and a good general combining ability, were used as female parents and Gaspé as the pollinator. The joint scaling test allowed to analyze the means of the parents, F1’s, F2’s and the two backcross generations for each one of the five possible combinations. Cumulative heat units from planting to tasseling were used as an earliness index. Only two crosses fitted to the additive-dominance model. For the other three crosses, the single gene effects and interactions were better explained by the six parameter model. The number of effective factors controlling the trait was estimated between 4 to 10. As the additive effects widely overcome the dominance effects, a consistent progress can be predicted using conventional selection methods.

Key words: maize, earliness, tasseling, gene effect, selection method, Zea mays sp. mays.