Multivariate analysis of selection in experimental populations derived from hybridization of two ecotypes of the annual plant Diodia teres W. (Rubiaceae)

Morphologically variable F₂ genotypes derived from hybridization of coastal and inland ecotypes of Diodia teres were used to identify selection on morphological traits in the natural habitat of each ecotype. These ecotypes occur in very different habitats, and have evolved pronounced morphological differentiation. Directional selection favored traits of the native population at the coastal habitat, but less so at the inland habitat. Selection was of sufficient strength to create the observed morphological differences between ecotypes in 25-100 generations, given constant selection and sufficient genetic variation. Many traits entered into strong but evanescent interactions affecting particular components of fitness. -from Author