ABSTRACT
Nitrogen fi xation in legumes plays a key role in the maintenance of crop production. The most important legume crops including cool season grain legumes (pea, faba bean, lentils, grass pea, chickpea, lupins) are able to use atmospheric nitrogen in symbiotic association with rhizobia, that renders them partially or fully independent of nitrogen fertilizer. However, this property is often not considered in new cultivar development programs, and worse, non-reasonable amounts of chemically synthesized nitrogen are many times applied to legume crops that are otherwise capable of nitrogen fi xation. General aspects of the symbiotic nitrogen fi xation process, together with a review of the knowledge accumulated on the legume-rhizobia interaction will be the subject of this chapter. In addition, the importance and possibilities of breeding for enhanced nitrogen fi xation in crop legumes are discussed.
