Kiwifruit: the wild and the cultivated plants.

The defining characteristics of the genus Actinidia, to which kiwifruit belong, are described. Taxonomic relationships between the two important cultivated species, A. chinensis and A. deliciosa, are summarized, and the history of the domestication of these two species is outlined. Most commercially important kiwifruit cultivars are selections from the wild, not the result of planned breeding programs. There is great variability within the genus, and it is therefore important when considering the possible contributions of kiwifruit to the human diet to define the particular genotypes or cultivars used in experimental studies and the origin and postharvest management of the fruit.