Comportamento silvicultural de progênies de erva-mate (Ilex paraguariensis St. Hil.) em diferentes condições de sombreamento

Abstract

Istra (Ilex paraguariensis St. Hil) belongs to the family Aquifoliaceae, a species found in the understory of Araucaria angustifolia, which is of great economic, social and cultural importance. The objective of this work was to implant and monitor a plantation composed of three progenies of yerba mate (Ilex paraguariensis St. Hil.), In order to evaluate their silvicultural behavior in three shading conditions. The planting was carried out in three distinct environments (sub-forest of native forest, sub-forest of planted forest and full sun) at UTFPRDois Vizinhos, in September 2016, spaced 1,5m x 1,5m. 180 seedlings of three progenies (15, 16 and 17) were planted in four linear plots of five seedlings in each environment and each progeny. The preparation of the soil was done before planting, through scarification in full sun, and opening of pits with coveador motorcycle in the other two environments. The plants were evaluated over nine months, measuring the following variables: Survival, Total height, Number of leaves, Collar diameter and Cup diameter. The data were submitted to a multivariate statistical analysis, and a discriminant analysis was performed (Linear Discriminant of Fischer) and later the Wilks Lambda and Chi-square tests were performed. The highest percentages of survival were in the native forest sub-forest (15: 95%, 16: 100% and 17: 100%), while the lowest were in full sun (15: 60%, 16: 65% and 17 : 55%). The number of leaves was higher in the sub-forest of planted forest (15, 27 and 23), the native forest understory presented the lowest values (13 leaves in all progenies). The highest heights were found in the understory of planted forest (15: 31,31 cm, 16: 42,09 cm and 17: 35,02 cm), the worst values were presented in full sun (15: 24,13 cm; 16: 24.23cm, and 17: 23.31cm). The progeny that presented the best results in all environments was 16, which in the sub-forest of native forest and in the full sun presented proximity of values with the progeny 17.