Nodulation Patterns on Legumes

Abstract

Fred, Baldwin and McCoy¹ made the generalization that effective strains of Rhizobium produce few but large nodules, usually located on the upper root system of the host, whereas ineffective strains form numerous small nodules widely distributed over the root system. Subsequent detailed studies on the physiology of nodulation have been summarized by Nutman², with a hypothesis relating nodule density on the root to the number of preformed foci, themselves determined by genetic factors affecting root morphogenesis. Dart and Pate³ recently reported studies concerning the effects of delayed inoculation on nodule production and position.