Abstract
There is much empirical evidence that crops grown as diverse populations (multilines, varietal mixtures, intercrops and rotations) suffer less from plant pathogens than the equivalent crops grown as pure stands. However only in the case of intraspecific genetic diversity and for above-ground pathogens has there been a mechanistic explanation of the disease reduction observed. For intercropping there is little known about mechanisms of disease reduction especially for soil-born plant pathogens, and for crop rotations within and between years the explanations are either trivial (host vs nonhost) or contradictory (as in the case of the development of suppressive soil microflora). Crop diversity itself may lead to enhanced soil microbial diversity , but again the role of microbial diversity in disease suppressive ness is often anecdotal and rarely tested rigorously. This project will give more insight into how interspecific diversity of crops affects soil-borne plant pathogens and vice-versa. Furthermore the results of this project will provide substantial information on how intercropping can be used in agriculture as a management practice that enhances the activity of resident and/or introduced micro-organisms antagonistic to soil-borne plant pathogens. The scientific objectives of the project are to: ( 1) Describe and quantify disease reductions in mixed cropping systems when challenged by both host-specific and generalist soil-born fungal plant pathogens; (2) Describe and quantify the effects of soil-borne fungal plant pathogens on competitive interactions between crops in diverse populations; (3) Investigate hypothesized mechanisms of disease reduction for representative soil-borne fungal plant pathogens; (4) Determine the potential for manipulating crop diversity as a means of introducing antagonistic micro-organis
Netherlands