Can arbuscular mycorrhiza fungi and NPK fertilizer suppress nematodes and improve tuber yield of yam (Dioscorea rotundata ‘cv’ ewuru)?

Abstract

Poor soil fertility and nematodes limit yam tuber yield and quality. Arbuscularmycorrhizal fungi (AMF) and fertilizers may suppress nematodes and improve yamproductivity. We evaluated the extent AMF and fertilizer suppressed nematodes andimproved yam performance. Tuber weight, mycorrhizal colonization of roots andnematode populations were evaluated with eight treatments; Control (No amendments),90-50-75, kg N- P2O5-K2O ha-1 (NPK), (AMF) (2g/kg soil), nematodes (5000 juvenile/pot),and their combinations. Tuber weight was higher in NPK+AMF and NPK+nematodetreatments than AMF+nematode. NPK+AMF improved tuber weight by 17.5% and 32%compared with sole NPK or AMF respectively. Compared with control, nematodes did notreduce tuber weight but, AMF+nematode reduced it by 49.4%. NPK reduced AMFcolonization of roots and reduced nematode population on tuber, in roots and soil by 34%,42.6% and 41% respectively. NPK+AMF treatment was superior to either NPK or AMF inimproving tuber yield while NPK was superior to AMF in suppressing nematodes in roots,soil, and tuber.