Genotypic variation of N2-fixing common bean (Phaseolus vulgaris L.) in response to iron deficiency

SummaryIn calcareous soils, the yield of grain legumes is often limited by the lower availability of iron (Fe), especially when they depend upon symbiosis with root nodule bacteria for their N nutrition. In order to explore the variability of responses of N2-fixing common bean to Fe deficiency the common bean white-seeded lines Striker and Coco blanc, and coloured-seeded lines SVM-29-21 and ARA14 were inoculated with Rhizobium tropici (CIAT 899) and cultivated hydroaeroponically with a N-free nutrient solution supplied or not with 45 μM Fe. Differences among lines were observed: Fe-deficiency-induced-chlorosis on young leaves was earlier and more severe in some lines than others. Nodule development and N2-fixing capacity was less affected in line ARA14 which preferentially allocated Fe towards nodules. Results suggest that Fe use efficiency for symbiotic nitrogen fixation (FeUE SNF) could be used to screen tolerant bean lines to Fe deficiency in condition of symbiotic nitrogen fixation.