Different reproductive traits are compared among wild a 1d cultivated populations of Phaseolus coccineus L., growing along an altitudinal gradient (2,200-3,000 m) and under different environmental conditions. It is suggested that the high altitude populations are genetically isolated from both the cultivar and wild populations at low elevation due to differences in pollinators, phenology, breeding systems and quantitative floral attributes. The high elevation wild populations show autoincompatibility; this trait is absent in the cultivar and low elevation wild populations. High elevation populations produce fewer flowers per inflorescence and proportionally more fruits than the other populations. The cultivar produces fewer seeds per pod, but they are eight times heavier than those of the wild populations. Many similarities between the low elevation wild populations and the cultivar were detected, except those attributes directly affected through selection by domestication, such as the number and weight of seeds per fruit. Intermediate phenotypic traits in the low elevation wild populations suggest genetic flow with the cultivar.