NUMERICAL TAXONOMY APPLIED TO CUCURBITA RELATIONSHIPS

In a numerical study of taxonomic relationships in Cucurbita, the inclusion of F₁ interspecific hybrids did not materially alter the species grouping in the phenogram. The F₁ interspecific hybrids tend to cluster with one of the parent species or species groups unless the parents are widely divergent. Also, the F₁ interspecific hybrids between wild and domesticated species cluster with the wild parent Both parent species or species groups of an F₁ interspecific hybrid can usually be determined from Q-correlation values. It is essential that compatibility relations be determined between species; i.e., species groups must be established before Q-correlation values can be successfully used in determining the parentage of hybrids. Undescribed collections can usually be correctly placed in the proper species group.