Endophyte infection, nutrient status of the soil and duration of snow cover influence the performance of meadow fescue in sub-artic conditions

Neotyphodium endophytic fungi are beneficial for certain cultivated grass species by increasing the stress tolerance and herbivore resistance of their host plants. These grass endophytes have been widely studied in temperate regions. Endophyte-infected grasses are also cultivated in sub-artic conditions, but studies on the effects of endophyte infection on grasses under conditions of prolonged snow cover are scarce. A 2-year field experiment was conducted with two originally endophyte-infected meadow fescue ( Schedonorus pratensis ) cultivars. The growth and reproduction of endophyte-infected (E+) and endophyte-free (E−) plants of two cultivars at two sites, differing in nutrient status and duration of snow cover, were compared at the latitude of the Arctic Circle in Finland. Endophyte infection enhanced plant performance most at the site with the higher nutrient status and the shorter duration of snow cover. The difference in growth between E+ and E− grasses increased during the second growing season and was most pronounced in the reproductive investment of grasses, but the benefits of endophyte infection for reproductive mass were cultivar-dependent. At the site with the lower nutrient status, costs of endophyte infection on the vegetative growth of grasses were found. The results suggest that Neotyphodium infection may benefit meadow fescue in sub-arctic conditions but the extent of the effects is dependent on the cultivar and the environment.