The plastic greenhouses are considered an homogeneous environment, however, that affirmative is not tested, because production variations exist among plants, influenced by several external factors. There is a lack of information related to techniques of experimental designing in these environments. Experiments were installed in the Crop Science Department/UFSM with the culture of chili in plastic greenhouse in two seasonal seasons, in order to study the variability of the production around the average, for each harvest and in the total yield, in different plot size. With the variances homogeneity test, for each harvest and total yield, the dispersion on the production around the average, it was verified that there is a high heterogeneity in the distribution of the production among the experimental plots in protected chili culture, and that plots of 14 plants in the line had reduced the variations of soil. The randomized blocks design in the line is adequate for these environments.
Capsicum annuum; production variability; planning; experimental precision
