The objective of this work was to determine the suitable sample size, to detect statistical differences in the analysis of variance of xylem characters, in annual shoots of avocado trees. For this, xylem characters of three trees with contrasting height were registered for frequency, area, perimeter and diameter of xylem vessels. Starting from 50 observations from each tree, a total of 5.000 non parametric bootstraps were done for each of the replicates from 2 to 50 microscopic fields. Starting from a sample size of 15 replicates, the deviations in the five statistical estimates are minimal, so it is proposed as the minimum for sampling the mentioned variables.
Persea americana; variance analysis; bootstrap; xylem vessels
