Horticultural protocols for experimental studies of eyebrights (Euphrasia, Orobanchaceae): Student Project

Parasitic plants are particularly challenging to cultivate as the growth conditions must be suitable for the parasite, the host, and their interaction. Here, we review our progress growing eyebrights (Euphrasia), a group of hemiparasitic plants found in diverse habitats in Britain and Ireland. We consider the protocols required to grow them under a range of conditions, including the growth of un-hosted seedlings in the laboratory, mature plants in pot trials, commercial scale quantities in cultivated fields, and the establishment of plants in the wild. We draw on recent research results from pot experiments, and also present new results from preliminary field trials and reciprocal transplant experiments in nature. We find that the growth conditions for Euphrasia must use cold stratification to break seed dormancy, use a suitable host species and manage the host to avoid competition, and mimic their natural environment in terms of free draining soil and unshaded conditions. While Euphrasia can be successfully grown in different environments, more reliable protocols are required for establishing mature plants under natural conditions.