Impact of Endomycorrhization on the Nursery Growth of Seedlings of a Threatened Ivorian Forest Species Pterygota macrocarpa K. Schum (Malvaceae)

Abstract

Aims: Pterygota macrocarpa, a common species in the forests of Côte d'Ivoire, is threatened with extinction due to overexploitation. Protective measures for P. macrocarpa could consist in the integration of arbuscular mycorrhizae in the reforestation of this species. The objective of this study was to evaluate the impact of arbuscular mycorrhizae inoculation on the resistance and development of P. macrocarpa plants. Study Design: The design is completely randomized and includes one (1) plant species (Pterygota macrocarpa), three (3) treatments (local inoculum 1, commercial inoculum 2 and non-inoculated control) and 20 seedlings per treatment. Place and Duration of Study: The experimental study was set up at the border of the experimental forest of the Northern site of INP-HB (National Polytechnic Institute Houphouët-Boigny, Yamoussoukro, Côte d’Ivoire) from February to May 2018. Methodology: Thus, from seedlings collected in the arboriculture of the INP-HB of Yamoussokro, the effects of mycorrhization through treatments on the mineral nutrition and on the growth parameters of P. macrocarpa were evaluated during 120 days of culture in nursery. Results: The mycorrhised plants survived 100% while the control plants had 90% survival rate. The mycorrhizal intensity of the roots was 19.21% for inoculum 1 and 10.40% for inoculum 2. The plants treated with inoculum 1 had the highest mineral content, especially phosphorus (0.3 ppm) and nitrogen (2.6%). The vegetative growth of inoculum 1 treated plants was more accelerated than that of the other two treatments. Local inoculum 1 was more effective than commercial inoculum 2. Conclusion: The integration of local mycorrhizal inocula in the reforestation of P. macrocarpa seedlings could be a sustainable solution for the restoration of degraded forests.