Soil properties shape the arbuscular mycorrhizal status of common bean (Phaseolus vulgaris) and soil mycorhizal potential in Kabare and Walungu territories, Eastern DRCongo

Abstract

Common bean (Phaseolus vulgaris) is the main leguminous crop grown in South-Kivu province. However, there is a scarcity of information concerning the soil mycorrhizal potential, natural mycorrhization and the spore density of arbuscular mycorrhizal (AM) fungi associated with P. vulgaris in South-Kivu province. In this study, rhizospheric soil and roots samples have been collected in Kabare and Walungu territories in famer’s field (three localities in each territory) to determine the bean natural mycorrhization rate, AM spore density and the soil mycorrhizal potential in relation with soil chemical properties. We founded that bean root colonization was high in Katana, Kavumu and Miti, and low in Lurhala, Walungu centre and Nduba. Katana and Kavumu showed a high number of spores (242.9 ± 37.8 and 183 ± 13.1 spores.100g− 1 soil, respectively) compared to other sites. Soil mycorrhizal potential was higher in Katana, Kavumu and Miti sites, located in Kabare territory (10.8 ± 0.7, 9 ± 1.3 and 8.8 ± 0.9 AM propagules g-1 soil). AM potential was positively and significantly correlated with bean mycorrhizal colonization (p < 0.0001). Increasing soil P content significantly decreased mycorrhization frequency and intensity (r=-0.69, p < 0.0001 and r=-0.54, p = 0.002, respectively) and the soil mycorrhizal potential (r= -0.87, p < 0.0001) regardless of the study site. While soil pH positively affected the mycorrhizal colonization (r = 0.73, p < 0.0001 and r = 0.54, p = 0.002, respectively) and the soil mycorrhizal potential (r = 0.78, p < 0.0001). This study revealed a strong variation in bean mycorrhizal status and soil mycorrhizal potential across sites. Site-specific AM fungi morphotype identification and inoculum production should be considered to improve bean productivity.