In this project we develop or optimise bioassays in order to obtain controlled infections for the evaluation of host resistance or to determine the efficacy of traditional or alternative plant protection products.
For a range of pathogens we determine optimal methods for pathogen growth, inoculation techniques and environmental conditions, also taking the diversity within the pathogen population (differences in aggressiveness or different pathotypes) into account. This should lead to more efficient development or more sustainable use of resistant cultivars and crop protection products.
Optimised bioassays are applied within ILVO projects (e.g., as part of breeding activities) but are frequently also offered as a service to external parties such as advisory services research centres and commercial breeding companies. Bioassays developed over the past years include the following combinations: Puccinia horiana on chrysanthemum, Rhizoctonia solani on maize, Cylindrocladium and Phytophthora on azalea, Cylindrocladium buxicola and Volutella buxi on boxwood, Phytophthora ramorum on rhododendron, Phytophthora cinnamomi on ivy, Phytophthora cactorum on pansy, Puccinia coronata on ryegrass, and Podosphaera pannosa and Diplocarpon rosae on rose. Especially the first two combinations are frequently used by external parties.
This service eventually leads to resistant breeding material or cultivars, or contributes to the registration process of plant protection products (e.g., via a GEP-experiment in collaboration with an extension research centre). In some cases the assays are not used as part of the breeding process but rather for the evaluation of the resistance level in existing cultivars. For example, in case of Rhizoctonia and maize, this will lead to the listing of the resistance level against this pathogen on the official catalogue of varieties of agricultural plant species.