Root nodule and rhizosphere bacteria for forage legume growth promotion and disease management

Abstract

Forage legumes are essential for an efficient animal-based agriculture. This chapter describes microbial-based strategies for improving legume establishment. It focuses on the use of root nodule bacteria for growth promotion and rhizosphere pseudomonads for disease management. The technological system for biological nitrogen fixation deployed in Uruguay is discussed as a model. We analyze the significance of the characterization of rhizobial strains, selection and culture collection, as well as inoculant production and quality control. Knowledge of the biodiversity of introduced and local populations of rhizobia is discussed for the design of successful inoculation strategies. On the other hand, the exploitation of the highly diverse genus Pseudomonas is considered for the biological control of Pythium seedling diseases. By testing large local collections of fluorescent Pseudomonas, strains can be selected with enhanced disease-suppressing and plant growth-promoting abilities to develop bacterial inoculants. The ecology of forage legume microbes is recognized as a key tool for developing sustainable agricultural systems.