Der einfluß einiger mikroskopischer pilze auf die symbiose der knöllchenbakterien und sojapflanzen

Summary When strains of Rhizobium from soybean roots were isolated in 1980, at the stage of flowering, a number of nodules with pathological lesions were observed. Some species of microfungi: Fusarium oxysporum, Fusarium solani, Gliocladium roseum, Thielaviopsis basicola and Trichoderma lignorum were isolated from nodules with these symptoms. It was supposed, that these species of fungi have a direct share in evolving the diseases and exercise influence on Rhizobium -soybean symbiosis. Therefore soybean plants grown in sterile sand were inoculated with Nitrofix inoculating powder, then four weeks later with conidium-suspension of the fungi, too. Weight of shoot and pod, protein content of plant and the number and weight of nodules were reduced by each of the isolated fungi. The greatest quantity of diseased nodules was caused by Thielaviopsis basicola .