Situational analysis of abiotic and biotic factors influencing abundance of tissue culture and non-tissue culture bananas in smallholder farms in Western Uganda

Abstract

Bananas are, in Uganda primarily, grown for domestic consumption and regional trade. Production is constrained by several factors such as declining soil fertility, pests and disease, and erratic rainfall. Tissue culture banana were introduced partly to solve some of the challenges in banana production, though uptake of such technologies by smallholder farmers is still low. A survey on plant parasitic nematodes, banana weevils, and selected soil factors was done to analyse their effect on the abundance of tissue culture banana (TCB) and non-tissue culture banana (NTCB). Soil and banana root samples were collected from heterogeneous on-farm orchard conditions in smallholder farms. Composite banana root samples and composite soil samples were collected from banana orchards already established by farmers. A total of 1,280 genets from 20 orchards were obtained. Composite soil samples were analysed for pH, potassium, phosphorus, nitrogen, and organic matter. Endo-parasitic Helicotylenchus multinctus, Platylenchus goodeyi, Radopholous similis and Meloidogyne spp were isolated from the composite root samples. Banana weevils were captured using the disc-on-stamp and split-pseudo stem traps. Redundancy Analysis (RDA) and logistic regression were run to ascertain the relationship between variations in biotic [Nematodes and weevils] and abiotic [pH, K, Av.P, N, and OM] factors affecting the abundance of the banana type. Canonical eigenvalues showed that both biotic and abiotic variables significantly affected the abundance of TCB and NTCB banana types. Abundance of TCB was influenced by the banana weevil (P<0.05) than it was by nematodes in the same farmers’ fields. Infestation with nematodes for TCB and NTCB banana types was not different (P<0.05). The banana weevils were significantly (P<0.05) distributed within the districts. Relative abundances for the pH, phosphorus, potassium, nitrogen (%), organic matter (%) within districts were significant (P<0.05). Variations in soil pH and nitrogen availability resulted in significant interactions (P<0.05) that affected the abundance of the TCB types more than their contribution to the abundance of NTCB. The awareness that the interactions between nematodes, banana weevils, phosphorus, nitrogen, potassium and pH determine the abundance of banana types is important in shaping the adoption and production of the adopted banana technology. Mitigation of acidic pH, K, Av.P, N, and OM for soil fertility and reduction of the abundance of nematodes and weevils below the threshold will enhance banana production among small holder farmers in Uganda.