Variations of several morphological characters of Petunia axillaris in Uruguay

Petunia axillaris seedlings from 102 localities in Uruguay were examined for the range of morphological variations. When three floral characters and seven vegetative characters that are horticulturally important were measured, they varied significantly between the two subspecies axillaris and parodii, except for plant height and leaf length. Cluster analyses of variations of characters, relative to the population locality, revealed that plant height and width and number of lateral stems segregated into six growth forms: upright, medium, compact, lax, small prostrate, and large prostrate. These growth forms seemed to represent ecotypical groups rather than taxonomical. The relationship between the growth forms and the environment of native habitats are discussed. In addition, we noted the growth forms that have horticultural potentials and their application to breeding.