Abstract

"Lotus species are very important for their interesting agricultural potential, their capacity to fix atmospheric nitrogen and adaptation to low input agricultural systems. In this study, the most utilized species in the country were used: L. corniculatus or birdsfoot trefoil; L. glaber or narrowleaf trefoil; and L. uliginosus or big trefoil. With the objective of determining the nitrogen fixation capacity and comparatively evaluating the symbiotic fixation of the different strains, a trial under controlled conditions was conducted with 68 indigenous strains of Mesorhizobium loti and Bradyrhizobium sp. (Lotus). Culture tubes with Norris and Date solution without nitrogen were utilized. Emerging seedlings were inoculated with one of the native strains and evaluated 45 days after inoculation. Plants without nitrogen and with nitrogen were utilized as controls. The plants were cultivated in a controlled environment with a photoperiod of 16:8 (light: dark), at 24