In Vitro Physiological Characterization of Strains from Transcontinental and Endemic Morchella Species from...

True morels (Morchella spp.) in South America are poorly documented, despite their high gastronomic and ecological value. In this study, morel ascomata were collected from various environments in south-central Chile, and their in vitro physiological performance was characterized. The endemic species Morchella andinensis, along with the transcontinental M. tridentina, M. eximia, and M. importuna, were identified, pure isolates obtained and then cultivated under various conditions. The carbon supplements had a significant effect on mycelial performance, with mannose and pectin yielding high growth rates (~13 mm·day^-1) and biomass production (~100 mg·plate^-1). Carboxymethylcellulose consistently reduced growth across all strains. Depending on the strain, organic nitrogen supplements such as peptone and amino acids promoted growth more than inorganic nitrogen such as ammonium sulfate. Most strains demonstrated higher performance at pH 7.2-8.5 and 24 °C, and sclerotia formation was strongly strain-dependent. An exploratory principal component analysis (PCA) descriptively summarized the standardized physiological response profiles of the eight selected strains. In this analysis, M. importuna strains were associated with generally higher growth responses, while M. tridentina T140 and M. eximia E87 showed comparatively lower responses. The M. andinensis strains occupied intermediate positions in the multivariate space. The results indicate significant physiological differences among Morchella strains. This underscores the importance of strain-level evaluation as a preliminary step for future studies on strain preservation, artificial cultivation trials, and biotechnological investigations of morels in Chile.