Artificial neural networks unravel the key factors influencing in vitro solid culture of Boletus reticulatus mycelium for chestnut mycorrhization

Artificial mycorrhizal inoculation has been utilized to improve not only tree growth and development but also to enhance mushroom production for commercial purposes. Traditionally, mycelium for mycorrhizal incubation of chestnut trees has been obtained from carpophores and/or spores, as it can be easily prepared, relatively affordable, and does not require specialized equipment. However, this approach is seasonally dependent and may carry mycelia/spores from other fungi and even pathogens, hindering the selection of specific genotypes. To overcome these limitations, the production of mycelium through in vitro culture using pure single and elite strains is highly recommended. Currently, limited knowledge exists regarding the growth conditions and nutritional and climatic requirements of Boletus reticulatus. This study aimed to identify the key factors influencing the mycelium growth of B. reticulatus under in vitro conditions in solid culture. The factors studied (5) included: sampling site, mycelial strain, culture time, temperature and medium composition. Specifically, their impacts on the presence/absence and the mycelium growth area were analysed over 59 days. The results were analysed using neurofuzzy logic, a combination of artificial neural networks and fuzzy logic. The analysis revealed that only culture time and mycelial strain were the key factors influencing the presence/absence of growth, whereas culture time, mycelial strain and culture medium were the key factors influencing the growth area. Additionally, the interaction between culture time and temperature also played a significant role.