M. Tech. Agriculture / The high nutritional value of pigeon pea explains its importance in the diet of smallholder farmers in Africa. Pigeon pea grain is used in many forms. Pigeon pea is consumed mainly as dhal (split-grain) by the Asian community in South Africa, while the African population uses the dry grain. The leaves and stems of pigeonpea serve as an excellent feed for livestock or as fuel wood. Low soil N often limits plant growth and symbiotic N2-fixation offers opportunity to overcome low soil N levels for increased crop yield. However, N is also known to be the most commonly deficient nutrient in soils. Biological N2-fixation is therefore a cheaper source of N for improving crop yields. Because symbiotic systems contribute great amounts of N input into natural and agricultural ecosystems, legume N2-fixation is considered cheaper source of N for poor farmers. It is also more sustainable and environmentally friendly compared to fertilizer N. Nitrogen-fixing microorganisms therefore provide an alternative to inorganic fertilisers which are expensive and not easily accessible to poor rural farmers. This study evaluated plant growth and symbiotic performance C accumulation, P nutrition and grain yield/quality in ratooned pigeon pea (Cajanus cajan L. Millspaugh) genotypes obtained from international crops research institute for semi-arid tropics.