Carry-over effects of soil inoculation on plant growth and health under sequential exposure to soil-borne diseases

background: and aimsmost plant-soil feedback and inoculation studies are limited to one growth cycle. we examined the effects of inoculation with eight plant-conditioned soils on chrysanthemum during two sequential growth cycles. the plants were also exposed sequentially to soil diseases. methods:in cycle 1, plants were grown in sterile soil inoculated or not with plant-conditioned soils, and exposed or not to pythium or root feeding nematodes. in cycle 2, new plants were grown in soil from cycle 1 or in new 100% sterile soil. plants were exposed again to pythium, or to soil with pathogens and nematodes collected from a commercial chrysanthemum greenhouse. results:after two cycles, effects of soil inoculation on plant growth were still present. chrysanthemum exhibited a negative conspecific feedback response, but this was less strong in inoculated soils. pythium or nematode addition did not affect plant growth. however, addition of pathogen-containing soil from the commercial greenhouse reduced plant growth in sterile soil but increased growth in plant-conditioned soils. conclusion:sinoculation with plant-conditioned soil can reduce the negative conspecific plant-soil feedback of chrysanthemum. our study further advances our understanding of the temporal dynamics of conspecific and heterospecific plant-soil feedbacks, and how they interact with soil-borne diseases.