An uniformity trial was carried out with tomate plants grown in a plastic greenhouse with an area of 24m x 12m. The total fruit yield of salad tomato cv. Monte Carlo was evaluated during 11 separat harvest. The basic plot was planted with three plants in the same row. The plants were grown in distances of 0.3m in the same row and by 1,0m between rows. All 24 plots were allocated in ten different rows. The results demonstrate that the completely randomized were more adequate with plots smaller than 18 plants in the same row. The yield evaluation in experiments with different traits using a same cultivar in plastic greenhouse should be conducted up to 30% of total yield. This is importam for more experimental precision and budged economy and time. Results showed that the minimal significance difference varies after 30% of the total yield, was harvested for three, nine and eighteen plants in each plot.
design; precision; plot size
