8 2 Theories on Centers of Crop Origination 作物起源中心学说 1. The theory of vavilov (1920) Outline of the theory 23-24 Origin center: Big diversity; Dominant characters Wild types Primary origin center; second origin center 2) The 8 centers of crop origination (p 24)§2 Theories on Centers of Crop Origination 作物起源中心学说 1. The theory of Vovilov(1920) 1） Outline of the theory p.23-24 ➢ Origin center: Big diversity; Dominant characters; Wild types Primary origin center; second origin center 2) The 8 centers of crop origination (p.24)