Determinants of the quality of plant products

From the point of view of the agronomist, quality is not only a sum of characteristics of crops to be reached at the field but also a question of organization between farms and agro-food chains which collect and transform these products. To study the determinant factors of quality impose to study its definition, production and guarantee as compromise between biologic and technical components on one hand and the economic components integrating coordinations among actors on the other hand. Some of these approaches are presented by showing the transfers of scale between the plot of land, the farm and the crop supply system of agro-food chains needed to resolve questions of quality.