A seed dressing combining fungal endophyte spores and fungicides improves seedling survival and early growth in barley and oat

Abstract

The use of beneficial fungi as crop inoculants is constrained by the need for application of fungicides because the pathogen controlling fungicides often concurrently suppress the efficacy of the beneficial mycobiont. Root endophytic fungi have been shown to improve agronomic traits in spring barley and may be less sensitive to the regularly applied foliar fungicides. We hypothesised that a consortium of fungal endophyte species applied as a seed spore dressing may improve the germination and subsequent growth of barley and oat seedlings. We tested a range of seed dressings to evaluate the effects of the endophytes: untreated seed, regular fungicidal dressing (triticonazole and prochloraz), endophyte seed spore dressing and a combination of endophyte and fungicide. We found significant increases in mean barley seedling length induced by the endophytes after 28 days of seedling growth at time points of up to 6 months from seed dressing. The increases in mean seedling length were greatest for the combined fungal endophyte and fungicide treatment. For the oat cultivar, we found even more substantial endophyte associated increases in mean seedling length. These results indicate that the endophytes tested here are persistent in a seed dressing, enhance early seedling growth, are fungicide tolerant and are competent in two different genera of cereal crops.