Vegetative and reproductive behavior of Brachiaria decumbens cv. Basilisk under different shade levels

Resumen

A field trial was conducted to study the morphological, productive, and reproductive characteristics of signal grass (Brachiaria decumbens cv. Basilisk), cultivated at 30 and 50 % shade and full sunlight. For the shade trials, black polyethylene was used because it retains the incident light. Biomass production (t ha-1), percentage of dry mass/plant (%), plant height (cm), number of plants/m2, weight of roots/plant (g/plant), index of specific foliar area (cm2/g), number of spikes/ha, and seed production (t ha-1) were assessed. The biomass production and the number of plants/m2 were similar in all the trials. In the shade environments, the plants had lower percentage of dry mass (22.01 and 23.24 %) and they differed (P < 0.05) from the trial at full sunlight (25.38 %). The shade levels (50 and 30 %) stimulated the root growth (7.31 and 4.59 g/plant), contrary to the plants at full sunlight (2.80 g/plant). The height and the index of specific foliar area reached higher values (72.80 cm and 111.62 cm2/g), with 50 % shade and they differed from the rest of the trials. The number of spikes/ha did not show differences between the trials, and varied between 344 and 621 thousands. The seed production was higher (P < 0.05) with 50 % shade and reached 0.054 t ha-1 in the first productive cycle. Brachiaria decumbens cv. Basilisk had favorable performance in the different shade levels. The further evaluation of the seed production potential in this species is recommended under the conditions of this study, with larger number of productive cycles.
Key words: shaded pasture, pasture ecophysiology, systems ILPF, signal grass.