Cytogenetical Studies in the Genus Persea (Lauraceae) : II. A Comparative Morphological Study on 61 Avocado Strains

In order to elucidate the variation in Persea americana complex (avocado) and ta know the genetical relationships among strains and among races, morphological characters of 61 different avocado strains were analyzed statistically. The analyses of variance on 30 morphological characters at four-months-old seedling stage so far recorded in these materials clearly demonstrated a great genetic diversity of the germ plasms. The great diversity agrees well with earlier studies. The analyses of variance also showed that 15 out of the 30 characters examined were useful in characterizing, at least, strains, and that 14 out of the 15 such characters were also useful to distinguish races of P. americana. When six scattering diagrams were drawn based on six pairs of two characters which showed high F values arnong races and exhibited different extents of correlation to each other, it was found that Mexican-race strains tended to have smaller sizes than Guatemalan- or West Indian-race strains. Closer relationships were observed in the scattering diagrams between Guatemalan- and West Indian-race strains. Thus the genetic relatedness between Mexican and other races was concluded to be less closer, as compared with that between Guatemalan and West Indian races.