Directed Inoculum Production of arbuscular mycorrhizal fungi – the state of the art

Since the mutualistic nature of arbuscular mycorrhiza (AM) had been discovered, an enormous amount of experiments elucidated the huge potential of mycorrhizal technology. Nevertheless, the predict-ability of mycorrhizal effectiveness (i.e. the quantitative measure of a pronounced effect) in agro-ecosystems and plant production systems remained low. On this background, Directed Inoculum Production (DIP) had been developed based on quantitative genetics. During the inoculum production process the ecological niche of an arbuscular mycorrhizal fungus (AMF) is considered, the effective ecological niche widened and population engineering included in large-scale inoculum production. This is done in order to place effective mycor-rhiza products on the market. This article reviews briefly the histori-cal development and the idea of DIP and its performance in the last 25 years. Recent and current scientific explanations for the variabili-ty of mycorrhizal effectiveness and future demands of research are outlined.