Cluster analysis is being used increasingly in plant breeding research
to reveal relationships among inbreds, hybrids, or varieties. However
, few software programs popular in agricultural research feature a pro
cedure for generating the dissimilarity matrix, which often serves as
input to the cluster analysis. The elements of this matrix are estimat
es of relationship for all possible pairs of subjects, computed using
the raw data and expressed in terms of disparity or distance. A comput
er program we have written in personal computer SAS code is designed t
o generate a matrix of dissimilarities (distances) between all pairs o
f subjects based on binary (0, 1) data recorded for each subject. The
user can choose among three association coefficients and between two t
ypes of distances to express dissimilarities. Data organization and pr
ogram output are illustrated by example.