Seed Shape of Castor Bean (Ricinus communis L.) Grown in Different Regions of Tunisia

Aims: Seed size, shape and colour intensity were compared in castor bean (Ricinus communis L.) grown in the field in twelve locations corresponding to four climatic regions in Tunisia. Study Design: Seeds were obtained from plants grown in the field in twelve locations corresponding to four climatic regions in Tunisia. Place and Duration of Study: Samples were taken in summer 2014 from plants growing spontaneously. Methodology: Size is estimated as the area of the seed images. Shape is measured by the roundness and J index that gives the percent of similarity of the figure plane of a seed with an ellipse. Colour is measured as gray intensity in seed images. Results: Among the parameters indicating seed shape, roundness varied more than J index. Values of J index were superior, thus J index describes better than roundness the shape of Ricinus communis seeds. Seed size and colour presented higher variation than magnitudes concerning