ABSTRACT:
The objectives of this research were to determine the optimum plot size and number of repetitions, to evaluate the fresh weight of pigeonpea ( Cajanus cajan (L.) Millsp.), in times and years. Eighty uniformity trials of 6m×6m (36m2) were conducted. Each trial was divided in 36 basic experimental units (BEU) of 1m×1m, totaling 2,880BEU. The fresh weight of plants, in each BEU was weighed. The agricultural year 2011/2012, were evaluated 16 trials at 127 days after sowing (DAS) and 24 to 139DAS. In 2012/2013, four trials at each of times (163, 167, 170, 174, 177, 181, 184, 188, 191 and 195DAS) were evaluated. The optimum plot size was determined by the method of maximum curvature of the coefficient of variation model and the means compared, among evaluation times and years, by Scott-Knott test. The number of repetitions, in scenarios of combinations of i treatments (i=3, 4, ..., 50) and d minimal differences between treatments means, to be detected as significant, 5% probability by Tukey's test, expressed in percentage of experiment avarage (d=10%, 15%, ..., 50%), was determined by iterative process until convergence. The optimum plot size to evaluate the fresh weight of pigeonpea is was 8.39m2. Four replications, to evaluate up to 50 treatments, are sufficient to identify, as significant at 5% probability by Tukey's test, differences between treatment means of 54.1% of the average experiment.
Key words:
Cajanus cajan (L.) Millsp.; experimental planning; experimental precision.
