Addressing edaphic constraints to bean production: the Bean/Cowpea CRSP project in perspective

Edaphic factors constrain bean production in most areas where this crop is grown. They include nutrient constraints particularly N and P deficiency, soil acidity including Al and manganese toxicity, and drought. The Bean/Cowpea Collaborative Research Support Program (CRSP) has supported research on edaphic constraints to bean production since its inception, the major partnerships involving the University of Wisconsin and EMBRAPA, Brazil (1981-1989) and the University of Minnesota and INIAP, Ecuador (1989-2002). Research over this period has emphasized cultivar and strain variation in nodulation and nitrogen (N-2) fixation, host strain interaction and coevolution, host and strain tolerance of soil acidity, and nitrogen fixation under phosphorus limited conditions. This paper reviews recent developments in these areas of nitrogen fixation research, but does so from the perspective of the Bean/Cowpea CRSP project. (C) 2003 Elsevier Science B.V. All rights reserved.