Allozymic variation in the widespread and cultivated Viola odorata (Violaceae) in western Eurasia

Abstract

Viola odorata has been cultivated for cosmetics and medicine in Europe since antiquity. The spread by humans has expanded its distribution considerably beyond its original range in parts of the Mediterranean region, south-western Europe, and western Asia. One hundred and sixty-five plants of V. odorata from 52 collection sites from throughout most of its native range were analysed for seven isoenzyme systems. Twenty-eight allozymic markers were obtained, twenty-five of which were geographically variable. A profound east-west differentiation separating Anatolian and Caucasian populations from European populations was detected, with Greek and Sicilian populations somewhat intermediate. Western European populations were rather homogeneous, suggesting a common origin, which also included the Canarian var. maderensis and the naturalized Scandinavian (and British?) populations. Cretan and Cypriot populations were apparently recruited from more westward stations. The possibility that the two allozymic groups of V. odorata reflect isolated Pleistocene refugia is discussed. V. odorata appears to possess more geographically structured variation than has been found in other cultivated and human-spread species in southern Europe. © 2006 The Linnean Society of London.