Effects of field inoculation of potato tubers with the arbuscular mycorrhizal fungus Rhizophagus irregularis DAOM 197198 are cultivar dependent

Sustainable agriculture is based on improving soil microbial activities through new practices including the use of biostimulants such as arbuscular mycorrhizal fungi (AMF). However, many factors, such as plant cultivar, influences the success of mycorrhizal inoculation in field. We investigated the impact of inoculation with Rhizophagus irregularis DAOM 197198 (AGTIV®, Premier Tech) on three potato cultivars ( Solanum tuberosum cv. Écrin, Fontane, Manitou ® Desmazières) in two microplots in North of France. In each trial, sampling was carried out (i) at the tuber filling stage to study potato development and nutrition, as well as bacterial and fungal diversity in the roots, and (ii) at maturity to determine tuber yield. Our results showed that inoculation (i) homogenize tuber calibre (ii) significantly increased potato yield and financial income for Manitou plants, (iii) homogenized the phosphate root-to-shoot ratio, and (iv) did not modify neither the taxonomic composition nor the relative abundance of bacteria, fungi and AMF associated with potato roots whatever the potato cultivar. Our results suggest that the positive effects of the inoculation with R. irregularis DAOM 197198 might depend on the potato cultivar, but further investigations are needed to understand the impact of different soils and agricultural systems on inoculation success.