Tamanho de parcela e número de repetições em centeio

Abstract

The objectives of this work were to determine the optimum plot size (Xo) and the number of repetitions to evaluate the fresh and dry matter, and the grains yield of rye (Secale cereale L.), and investigate the variability of Xo between two cultivars and five sowing times (fresh and dry matter), and between two cultivars and three sowing times (grains yield). Thirty uniformity trials were conducted to evaluate fresh and dry matter, and eighteen uniformity trials to evaluate the grains yield of rye. Each trial with dimensions of 6 m × 4 m was divided into 24 basic experimental units (BEU) of 1 m × 1 m. Fresh and dry matter of rye were evaluated in the 720 BEU, and grains yield in the 432 BEU. The Xo was determined by the method of maximum curvature of the coefficient of variation model. The number of repetitions was determined in scenarios formed by combinations of i treatments (i = 3, 4, ..., 50) and d minimum differences between means of treatments to be detected as significant at 0.05 of probability, by Tukey test, expressed in percentage of the average of the experiment (d = 10, 11, ..., 20% and d = 10, 12, ..., 30%). There is variability in optimum plot size only to evaluate the grains yield among the cultivars BRS Progresso and Temprano and among sowing dates in the rye crop. The optimal plot sizes to evaluate fresh and dry matter, and the grains yield of rye are, respectively, 3.43, 3.82 and 6.08m2. Six and seven repetitions are sufficient to evaluate fresh and dry matter, and the grains yield of rye in experiments with up to 50 treatments, and to identify, as significant at 5% probability by the Tukey test, differences among averages of treatments less than or equal to 20 and equal to 29.65% of the mean of the experiment, in designs completely randomized and randomized blocks, respectively.