Can orange fleshed sweet potatoes processing trigger farmers to use quality improved planting materials? Empirical evidence from selected regions in Tanzania

Production of orange-fleshed sweet potato (OFSP) in Tanzania is constrained by the underutilization of virus-free improved certified planting materials. The sustainable use of these planting materials leads to the constant demand of the planting materials by farmers which can be triggered from viable processing. We determine the viability of processing in the OFSP value chain and its contribution to the uptake of high-quality improved planting materials. Data for this study were collected by field survey method from 15 processors and 150 farmers. Purposive and three-stage random sampling methods were used in sampling. We adopted a mixed method of analysis using descriptive statistics, gross margin analysis, and econometric estimation of the multivariate probit model by means of a Simulated Maximum Likelihood (SML). We found no direct effect of processing to trigger the use of improved OFSP planting materials unless formalization of the supply arrangements between processors and farmers is institutionalized. However, it was economically viable to engage in the processing of OFSP. Processors were found to be generating a benefit of US$ 76/ton of OFSP processed with a margin to a total cost ratio of 19% implying a relatively low margin with significant processing costs. Seed renewal was low as 63.1% of the farmers used retained planting materials. Nevertheless, contractual arrangements with the processors increased the desire to use high-quality improved planting materials and the likelihood to source them from research institutes (p<0.05). Additionally, access to credit and a high level of specialization influenced farmers to source planting materials from local vine multipliers. Creation of market linkage and formalization of supply arrangements between processors and farmers and awareness creation on the economic benefits of seed renewal will increase the benefits generated by processors. This may contribute to the uptake of high-quality improved OFSP planting materials in Tanzania. Key words: Economic viability, orange fleshed sweet potato, processing, value chain, market linkage.