Institute of Agricultural Research Statistics, New Delhi
*Present Address: Statistician, Coordinated Maize Improvement Scheme, Division of Genetics, I. A. R. I., New Delhi.
Yield data on apple were collected from Vindraban orchard in Ramgarh district of Nainital in Uttar Pradesh for studying the effect of plot size on the variability, and optimum size of plot. The distribution of weight of fruit per tree was not normal. The coefficient of variation decreases with an increase in the plot size. The relation Y=ax−b (o ≤ b ≤ 0.5) where Y is the coefficient of variation for plot size of X trees was fitted. With a given experimental area, the smallest plot (single tree) is more efficient. The optimum size of plot obtained is 10 trees per cluster. The minimum number of replicates and number of trees required for a given percentage of standard error were obtained for different plot sizes.
