Arbuscular mycorrhizal dependency and responsiveness of maize varieties from South-Kivu, eastern Democratic Republic of Congo

The benefits of arbuscular mycorrhizal fungi (AMF) for the nutritional quality, yield and nutrient uptake by plant have been investigated in maize. However, the variability in mycorrhizal dependency (MD) and root colonization by AMF among maize variety groups is still poorly documented in the Kivu region. This study aimed to investigate the variation in mycorrhizal dependency to Rhizophagus irregularis among five maize varieties from South-Kivu and one from Senegal using a greenhouse experiment. AMF inoculation significantly influenced the intensity of root colonization, growth and physiology of maize varieties, while no change in root colonization frequency was observed. Three of six varieties used responded positively to AMF inoculation. For these varieties, inoculation with R. irregularis significantly improved plant height, stem diameter and SPAD values. The same significant positive trend was observed for maize total shoot and root biomasses (p < 0.05). Significant variation in MD was observed among maize varieties (p = 0.00012) and could be attributed in part to genetic and physiological factors controlling host/fungus compatibility. The non-metric multidimensional scaling (NMDS) analysis discriminated varieties into two main groups, including those with high MD (MD>5%) and those with low MD (MD < 5%). The analysis of similarity (ANOSIM) for the mycorrhizal inoculation effect index (R = 0.15 and p = 0.0013), suggested high variability for symbiotic traits. Three varieties showed strong MD and can be used in the field to optimize beneficial effects of AMF on maize productivity or to be used as parents in maize breeding program.