Desenvolvimento vegetativo e desempenho produtivo de cultivares de palma de óleo em fase juvenil em ecossistemas de savana e floresta alterada de Roraima

Abstract

The objective of this study was to evaluate the vegetative growth and yield performance of three oil palm varieties in the juvenile phase, identifying cultivars with better adaptation on savannah environment and changed forest of Roraima (Brazil). Two experiments were conducted in two locations and distinct periods: the first experiment, for the vegetative development, was conducted in Savannah area (with supplementary irrigation) of Boa Vista (State capital), the other was a changed forest area in the municipality of Caroebe (south of the State), conducted between August 2008 and April 2010.The second experiment for the performance was conducted between January and December 2011 in both locations. The cultivars were: BRS C-2528, C-3701 and BRS C-2301, arranged in randomized complete blocks experimental design with six replications. Eighteen monthly evaluations were made to evaluate the vegetative development, the number of emitted leaves, leaf length 4 (cm) and girth circumference (cm). The performance evaluations were made by 12 collections per month, were they: the number of bunches ha-1, average weight and total production of bunches ha-1. Individual and joint variance analyses were made. The Scott & Knott test (5%) was made for the comparison of the evaluated. The Pearson correlation coefficients (r) were estimated to the average values of the performance characteristics in each environment. In the changed forest environment, the cultivars presented a higher vegetative growth than savannah environment. All the cultivars had a similar vegetative development in savannah environment. The BRS C-2301 cultivar had best results in the forest environment having larger vegetative development considering the number of leaves and the fourth leaf length. The three cultivars in forest environment showed different productive performance between them, producing between 19 and 23 tons of bunches / ha / year, especially the BRS C-2301, which was the most productive, and showed potential for field use. In savannah environment the three cultivars showed a similar performance between itself, producing between 4,5 to 6,0 tons bunches / ha / year), it was a low production, when compared to those obtained in the changed forest environment. The highest yields of bunches in the savannah environment, were due to the production of higher number of bunches and were concentrated in the months of March, April and May (rainy season), while in the forest environment were due to the higher average weights of the clusters and were concentrated in the months of October, November and December (dry season).