The interior of a plastic greenhouse can be considered a heterogeneous environment due high variability in the production, being necessary the use of experimental techniques for improvement of the statistical inferences precision. Between the main forms to obtain experimental error reduction is the use of the optimal plot size that has special importance in experiments inside plastic greenhouse, where the experimental area is normally restricted to the preexisting installations. The aim of this work is to estimate the optimal plot size for fruit fresh biomass of chili pepper cultivated in plastic greenhouse and the relation of the equations parameters that determine it. It was conducted four blank experiments under plastic covering, each one with eight lines of 70 plants. The fruit fresh biomass was evaluated in each plant, identifying its position inside the greenhouse, by the line number, and its position in the line in each harvest. The optimal plot size was estimated and related with the parameters used for its estimate by the Pearson correlation coefficient. It was recommended the use of parcels with ten plants in the line or double line, tending to decrease. There wasn't consistency in the relation of the variables with the plot size.
Capsicum annuum L.; experimental precision; path analysis; yield heterogeneity index
