Diversity of Suillus Species Associated with Conifer Trees in North Western Himalayan Region of India

Abstract

The diversity of the genus Suillus has not been explored thoroughly from the northwestern Himalayan region of India. By virtue of this, several basidiocarps of the genus Suillus were collected from different parts of this region and characterized morphologically as well as molecularly. The present research work described 7 species of Suillus. Among these, 3 taxa namely, S. triacicularis sp. nov., S. indicus sp. nov., and S. himalayensis sp. nov., were new to the science while S. flavidus and S. placidus were new records from India. Attempts were also made to isolate the cultures from each basidiocarps collected. In total, 8 Suillus isolates belonging to five different species (S. triacicularis sp. nov., S. indicus sp. nov., S. himalayensis sp. nov., S. granulatus and S. sibiricus) were obtained from basidiocarps. All these Suillus isolates exhibited inter-specific as well as intra-specific variations in axenic fungal growth, extracellular enzyme activities, and in vitro mycorrhizal capacities with Pinus wallichiana seedlings. On the basis of fungal growth, enzyme activities, mycorrhizal colonization, and the effects on seedlings growth, biomass and nutrients content; S. sibiricus SNW06 and S. indicus SNW02 were found to be the most effective and suitable Suillus isolates for growth promotion of P. wallichiana seedlings and therefore selected for mass inoculum production. Optimization of various parameters for mass inoculum production of both the Suillus isolates resulted in a significant increase in the radial growth and biomass yield of both the selected Suillus isolates. Further, the effects of both the selected Suillus isolates and biochar amendment on P. wallichiana growth and rhizosphere properties were evaluated. Based upon the present investigation, S. sibiricus SNW06 was found to be an efficient mycorrhizal strain as compared to S. indicus SNW02 and therefore, recommended for the production of mycorrhizal P. wallichiana seedlings in forestry practices. Also biochar application to the soil, especially along with mycorrhizal inoculations, was found to be advantageous for improvement of growth and nutrients content of P. wallichiana seedlings as well as the soil physico-chemical properties and enzyme activities.