Today, several applications use machine vision to product quality control, military industry, health, agriculture, and others. The crop lines are important in agricultural production since they allow to maximize the crop area useful and autonomous navigation through the crop. The use of machine vision in crop lines has addressed problems such as planting, fertilization, plant protection, weeding, and harvesting. In this paper, a method for segmentation stage use both on Y.Cr.Cb Color Space and Hough transform to find the tree crop lines in U.A.V (unmanned aerial vehicles) images acquired over a mango tree plantation. The proposed method has 86 percent of efficiency.