Combined use of Pinus pinaster plus and inoculation with selected ectomycorrhizal fungi as an ecotechnology to improve plant performance

Pinus pinaster is an important forest species for environmental and economic reasons. Due to its importance, tree improvement plans aimed at the selection and use of phenotypically superior trees, designated by plus trees, have been established. It is known that ectomycorrhizal (ECM) fungi can improve tree survival and growth. Seeds obtained from P. pinaster plus trees have been used in forest nurseries. However, the effect of inoculation with ECM fungi on the performance of these plants has not been studied. We compared the performance of P. pinaster plants obtained from seeds of plus and non-plus trees to inoculation with different selected ECM fungi under conventional forest nursery conditions. In plants obtained from seeds of non-plus trees only those inoculated with Suillus bovinus + Laccaria laccata + Lactarius deterrimus had a significantly greater biomass and needles nitrogen concentration, while in plants obtained from seeds of plus trees this effect was seen not only in those receiving that same ECM inoculation, but also in those inoculated with Rhizopogon roseolus or Pisolithus tinctorius + Scleroderma citrinum. The best performance was that of plants obtained from seeds of plus trees and inoculated with R. roseolus or S. bovinus + L. laccata + L. deterrimus, with an increase in biomass of 2.2 and 2.0 times, respectively. This significant improvement was achieved without extra input of agrochemicals. The combined use of seeds obtained from plus trees and inoculation with selected ECM fungi can be an advantageous ecotechnological approach to improve nursery production of P. pinaster.