This paper analyzes the synergies/tradeoffs involved in the adoption of improved varieties of multiple crops in the mixed crop-livestock production systems of the highlands of Ethiopia A multivariate probit (MVP) model involving a system of four equations for the adoption decision of improved varieties of barley, potatoes, wheat and faba beans was estimated using a nationally representative data from a sample of 1469 farm households. Model results attested the existence of endogeneity in the adoption decisions of improved varieties of the four crops. The area shares of improved varieties of potatoes and faba beans are also found to have positive and significant effects on the likelihood of adopting improved varieties of barley and wheat and vice versa - indicating synergistic effects among the adoption decisions of the two groups of crops. On the other hand, the area share of improved varieties of wheat negatively and significantly effects the chances of using improved varieties of barley and vice versa - suggesting the existence of tradeoffs between the improved varieties of the two crops. The MVP results, therefore, provide evidence for the simultaneity and interdependence of the
decisions and intensity of adoption of the improved varieties of the four crops. Practical
training has positive and significant effects on the likelihood of adopting improved varieties of barley, potatoes and faba bean while secondary level education has positive and significant effects on the likelihood of adopting improved varieties of barley and wheat. Hence, efforts to increase adoption of improved barley, potatoes and wheat varieties would more likely be successful if accompanied with practical trainings and/or if directed to farmers with relatively higher levels of education. Farmers in Oromia and SNNPR Regions are found to be more likely to use improved varieties of barley, potatoes and wheat than those in Amhara Region.
