Six blackbean (Phaseulos vulgaris L.) experiments were conducted at different places and/or years aiming to estimate the ideal plot size. Grains yields were obtained from 160 plots in each experiment, each one measuring 0.5 x 1.0m. The results indicated that the ideal plot size would be formed by four 6m, long rows and 0.5m between rows.
black-bean; plot size; interclass correlation