A new method of constructing an augmented partial diallel cross plan using the group divisible partially balanced incomplete block designs of two associated classes with parameter      and  where  p and q are the primary and secondary lines. Here one or more primary lines are crossed with the secondary lines, and the PDC plan is used for the secondary lines. Only the GCA effects were estimated in the linear model, and the crosses were taken based on the primary and secondary lines excluding reciprocals. In the construction of APDC, each cross occurs a maximum of once. The variance of interline comparisons for GCA effects was developed, and also discussed the efficiency of APDC, which is higher; when the number of lines p and q increases, the efficiency factor  and the efficiency factor  per cross increase.

group divisible partially balanced incomplete block design, augmented partial diallel cross (APDC), general combining ability, incidence matrix and efficiency.