Selection of Wetland Rice Genotypes for Associated Biological Nitrogen Fixation

Abstract

Experiments performed using 15N labelled N2 gas have demostrated that rice grown under wetland conditions is able to obtain a significant contribution from plant-associated biological nitrogen fixation (BNF) (Eskew et al., 1981; Yoshida and Yoneyama, 1981). N balance experiments performed in pots by App et al. (198 6) showed that different genotypes differed in their capacity to benefit from this source. Wetland rice genotypes grown in Brazil exhibit large differences in their responses to fertilizer nitrogen, and in their capacity to accumulate nitrogen in low fertility soils when nitrogen is not applied, suggesting that some genotypes may obtain significant contributions from associated BNF.