Experiments in agriculture and allied sciences often show that the response on a plot or unit under consideration is affected by the treatments applied on neighbouring plots. As a result, the estimation of treatment differences may deviate because of this interference. The allocation of treatments in such situations plays a vital role which can be achieved by using the Neighbour Balanced Incomplete Block Design (NBIBD). In the present study, left and right neighbours of a specified order for a treatment applied to the particular plot are studied. A general systematized method to find these neighbours for any of the treatment has also been developed by using the dual designs.
Key words: Neighbour Design, Dual Design, 𝑶𝑺𝟐 Series, Border Plots, Left & Right Neighbours.