Características morfogenéticas y estructurales de Megathyrsus maximus cv. Tanzânia-1 bajo intensidades de defoliación

Abstract

The effect of defoliation intensities (20, 30, 40 and 50 cm above soil level) on green dry matter (GDM) yield and morphogenetic and structural characteristics of Megathyrsus maximus cv. Tanzânia-1 were evaluated under field conditions in Roraima´s savannas. The effects of defoliation intensities on the GDM yields, leaf area index and leaf elongation rates was adjusted to the quadratic regression model and maximum values recorded with cutting at 40.9; 38.7 and 35.5 cm above soil level, respectively. The population tiller density, number of leaves plant-1 and leaf appearance rate was inversely proportional to the intensity of defoliation, while the opposite occurred for to medium blade length and leaf senescence rate. Apical meristem removing percentage was higher with increasing defoliation intensity. Aftermath regrowth showed close negative correlation with defoliation intensity level.