Chapter 5 - The potential of agroecological properties in fulfilling the promise of organic farming: a case study of bean root rots and yields in Iran

Abstract

Production of common or dry bean, the third most important food legume in the world, is threatened by root rot pathogens. Although considerable research related to the management of bean root rots has been performed, they continue to limit the productivity of this valuable crop. One of the main unknowns in plant pathology is a comprehensive knowledge on the complete array of agroecological conditions capable of suppressing soilborne plant pathogens. Systematic understanding of agroecological descriptors of the variability within root rot epidemics will certainly assist to develop environmentally friendly programs for disease management and sustainable production. In this context, the present chapter reviews the interactions of a wide range of agronomic and soil characteristics with root rot epidemics and bean production. In Zanjan Province, Iran, which was selected for our macro- and small-scale studies, bean root rots are caused primarily by Fusarium solani, Rhizoctonia solani, Macrophomina phaseolina, and Fusarium oxysporum. These fungal pathogens incite Fusarium root rot, Rhizoctonia root rot, charcoal root rot, and Fusarium wilt in bean crops, respectively. The variations resulting from the interactions of bean crops with the type, aggressiveness, and soil populations of root rot pathogens under given agronomic, environmental, and soil conditions are discussed in this review.