Pathogenicity of Pythium species on hosts associated with bean-based cropping system in south western Uganda

Abstract

A pathosystem is a subsystem of an ecosystem and is characterised by the phenomenon of parasitism. The bean-Pythium pathosystem consists of the host (bean), the pathogen (Pythium) and their host-pathogen relation. Of interest is how the pathogen causes pathogenicity on other crops and beans. To investigate this, screen house experiments were set up to test the pathogenicity of Pythium species derived from bean and other crops grown in association with beans. Pathogenicity was tested on maize (Zea mays), millet (Eleusine corcana), sorghum (Sorghum bicolor), peas (Pisum satium), susceptible bean variety (CAL 96) and resistant bean variety (RWR 719). The results indicated that distinct symptoms were observed in the roots and shoots of test crop species which are characteristic of Pythium infection. For instance peas had brownish watery stems and roots Also bean-derived pathogenic Pythium spp. were found to be more virulent than Pythium spp. derived from other crop species.