The study analyzes returns to investments in Nigers research and technology transfer system for millet, sorghum, and cowpea between 1975 and 1991. Sixty-eight percent of the countrys public-sector outlays for agricultural research and 58 percent of its agricultural researchers were devoted to research on these three crops between 1986 and 1990.
Link
http://agecon.lib.umn.edu/cgi-bin/pdf_view.pl?paperid=7366&ftype=.pdf