Revista Brasileira de Milho e Sorgo (Dec 2003)
MASS SELECTION FOR PROLIFICACY IN MAIZE GROWN IN NORMAL AND WINTER SEASONS
Abstract
Paterniani (1978) proposed the mass selection method for prolificacy in maize based on the high heritability of the traits and on the high and positive correlation between prolificacy and grain yield. Although the method has been efficient in some cases, presently there are only a few studies that confirm its results. The present work was carried out to study the efficiency of mass selection for prolificacy, investigating if its efficiency depends on plant density and whether two selection cycles can be carried out per year or not. Selection cycles started in 1994 in maize experiments in two different sowing dates: October (normal season) and January (winter season). The experiment evaluated six selective cycles in the two sowing periods, October and January, and included two plant densities: 33,000 and 55,000 plants ha-1. The prolificacy trait presented a small increase with selection, showing a small variability for this trait in the population. This was probably the reason why the gain from ear yield selection was not statistically significant. There was an undesirable increase in plant height and plant cycle with the selection. It was also observed that the mass selection for prolificacy didn’t depend on the plant densities used.
