Cemagref : Individual report

The results obtained in 1995 were very conclusive. On task C, mycorrhizal Douglas-fir cuttings were produced for the first time during the rooting phase. That success was obtained with two symbionts Laccaria bicolor S238N and Rhizopogon subaerolatus. Moreover, with Laccaria bicolor S238N, the inoculum developped in a peat-vermiculite medium led to high mycorrhizal rates, with a wide range of substrates. On the contrary, alginate beads gave generally very low mycorrhizal rates, except in one case (fumigated nursery soil). On task D, the inoculation of the rooted cuttings with Laccaria S238N in fumigated transplant beds always led to a very high mycorrhizal rate with the inoculated fungal strain. The growth performance was improved or not, depending on trials. Moreover, on two nursery sites, no interaction was found between inoculation and other cultural factors such as water regime and fertilising. After planting, the height growth and the survival rate did not vary between treatments. At last, interaction between Norway spruce genotype and inoculation with Laccaria bicolor S238N was studied (task F): less that 10% of the tested clones could possibly interact.