alfaDRA: A program for automatic elimination of variety self-proximities in alpha-design

Abstract When using alpha-design for plant variety testing under space restrictions, ex post design modifications must be implemented to prevent variety self-proximity on plots and, consequently, to prevent damage-induced loss of experimental information. This is done ad hoc for each experiment; the unsystematic modification is, however, commonly not only unable to resolve all existing proximities, but may introduce secondary undesired proximities. In this paper, a procedure is developed for the universal construction of modified alpha-design that covers all existing proximity constraints while keeping the efficiency level of the original design. Using extensive real data simulation, we validate the procedure and confirm high damage robustness of the modified designs. The procedure has been implemented as a Matlab function and is available as on-line supplement to the paper. The function enables to design the damage-robust experiments automatically using only standard computer equipment.