By Hans P. Binswanger-Mkhize, Derek Byerlee, Alex McCalla, Michael Morris and John Staatz. Presented at the ASTI-FARA conference Agricultural R&D: Investing in Africa's Future: Analyzing Trends, Challenges, and Opportunities - Accra, Ghana, December 5-7, 2011. http://www.asti.cgiar.org/2011conf