Influence of arbuscular mycorrhiza fungi inoculation on growth of sweet potato varieties in Nairobi county, Kenya

Sweet potato is an important food security crop cultivated mostly under temperate and mild tropical climatic conditions. The crop is vegetatively propagated using vines. However, its productivity in Kenya is lower than its genetic potential due to poor soil fertility. The productivity is constrained by phosphorus limitation in most agro-ecosystems. Phosphorus is one of the most important plant nutrients in sweet potato production but it is limiting in the tropical African soils. However, one of the feasible options is the use of arbuscular mycorrhizal fungi inoculant that enhances phosphorus and moisture uptake. A field experiment was therefore conducted in Peri urban area of Nairobi County to investigate the influence of arbuscular mycorrhiza fungi inoculation on growth of sweet potato varieties, during the long rains of 2017.The experiment was laid out in a Randomized Completely Block Design (RCRD) with two factors (two sweet potato x two mycorrhiza inoculation –plus or minus) and the treatments were replicated three times. Data on plant growth (vine length and number of primary stems) were collected and later analyzed using Genstat statistical software 15th edition and means separated by Tukeys 95% confidence level. The study results indicated that there were significance (Pd”0.05) differences amongst the sweet potato varieties and inoculation with AMF, leading to better performance in inoculation. Overall, mycorrhiza inoculation increased sweet potato growth. The study therefore recommends that farmers should be encouraged to use bio-fertilizers when planting their crops to realize better yields. Key words: Arbuscular mycorrhiza fungi, inoculation, Kenya, phosphorus, sweet potatoes