TWO CORN CULTIVARS RESPONSE TO DIFFERENT PLANTS DENSITIES UNDER TWO CONTRAST LEVELS OF NITROGEN, PANAMA, 1993-1994.

Abstract

In two consecutives years (1993-1994) were planted three trials, localized in Rio Hato and El Ejido, Republic of Panama. The experimental design was Completely Randomized Block in a split-split plot with three replications. The main plots were the Nitrogen rates (75 and 150 kg N/ha). In the split plots were put the plants densities (3.3 and 7.4 plants/m²), while, the cultivars were planted in the split-split plots (P-8916 and X-304C). The trial's objective was to describe the physiological and phenological standards parameters involved in the yield's elaboration, of the two principal cultivars sowed in Panama. In second place, to determine the corn yield response under two contrast rates of nitrogen. The high densities decreased the ears size (from 112.1 to 69.4 g). The optimal number of plant in all cultivars increased when the nitrogen levels improved from 75 to 150 kg/ha. According to statistical analysis, the cultivars-density interaction and density-nitrogen rates interaction was significative by variables: ear weight, anthesis silking interval (ASI), filling kernels and ears/plants. The ASI increased when the plant population increased. Factor like harvest index, leaves final number and ear's leaf number didn't affect the densities plants changes.