Fig. 3. A genotype + genotype x environment interaction bi-plot showing relationships among 20 environments (upper case letters followed by 2 or 3; 2 = 2002 and 3 = 2003). Cosine of an angle between vectors of any two environments represents correlation between the two environments. The unit of the linear map to the right of the graph is in degrees (the angle between the two extreme environmental vectors is about 140 degrees). The smaller the angle between any two vectors, the greater the correlation between them (see Yan and Kang, 2003).