TY - JOUR AU - Olmo, Harold P. TI - Introduction of disease and insect resistance in cultivated grapes JF - California Agriculture JO - Calif Agr Y1 - 1977/09/01 VL - 31 IS - 9 SP - 24 EP - 25 PB - University of California Agriculture and Nature Resources SN - 0008-0845 UR - http://www.ucanr.edu/sites/calagjournal/archive/?article=ca.v031n09p24 AB - Nearly all cultivated grape varieties, of which several thousand are grown commercially, derive their excellence in fruit quality from the Vitis vinifera grape. Although long considered a single species native to the temperate zone of Middle Asia, the vinifera is more of a complex of several ecospecies. Outlying relict populations also exist in some of the principal river basins of the Mediterranean area, and of the Rhine, Mostar, and Danube valleys. However, the role of these populations in the origin of cultivated forms is questionable.