Assessment of willingness to pay for quality sweet-potato planting materials: the case of smallholder farmers in Tanzania
In Africa, malnutrition and hunger continue to be major problems affecting developing countries, especially those in Sub-Sahara Africa. One of the major nutritional problems facing developing countries is micronutrient deficiency, vitamin A in particular. Biofortification, especially in staples can reduce prevalence of vitamin A deficiency and food insecurity. One of the biofortified staple is the Orange Fleshed Sweetpotato (OFSP). Recent interventions targeting reduction of Vitamin A deficiency have therefore promoted the growing and consumption of OFSP. However, sweetpotato growers face a major challenge of access to quality planting materials (defined as planting materials free from pest and diseases). Therefore, there have been efforts to supply cleaned vines of these biofortified crops in some countries, including Mozambique, Malawi, Rwanda, Ghana, Kenya, Uganda and Tanzania. However, biofortification of sweetpotato changes its color, taste and dry matter content. A study conducted in Uganda found that farmers are willing to pay for biofortified products, but only when they have information about the benefits such products deliver. The effects of changes in dry matter content and taste on farmers willingness to pay clean vines of biofortified crops are however unknown. This study analyzes willingness to pay (WTP) for quality planting materials of biofortified and non-biofortified varieties of sweetpotato and the factors that influence WTP for such materials. It also assesses differences in WTP by variety, region and agro-ecological zone between the biofortified and non-biofortified clean planting materials. The factors affecting WTP for quality planting materials were assessed using seemingly unrelated regression (SUR) model in order to accounts for possible correlation in the error terms. Analysis of variance method (ANOVA) was used to compare WTP by region, agro ecological zone and across different varieties. The data used in this study was collected from 732 farm households stratified by participation in a sweetpotato project implemented in Tanzania between 2009 and 2013. The results reveal that consumers are willing to pay highest for clean planting materials of New Polista, followed by Kabode and then New Ukerewe, Ejumula and lowest for Jewel indicating higher demand for clean planting materials of non-biofortified variety. Results of the SUR model indicated that farmer-specific factors (e.g., age and education), location factors (e.g., distance to markets), asset endowments factors (e.g., wealth and income), and varietal attributes (e.g., taste and yield) affect willingness to pay for clean planting materials but the effect is variety specific. This study concludes that willingness to pay for quality planting materials of biofortified OFSP and the non-OFSP varieties differs by region, agro ecological zones and varieties. It also concludes that farmers are willing to pay for quality planting materials of non-biofortified varieties, especially New Polista, than for the biofortified OFSP varieties. The implications of these findings are that farmers’ demand for clean planting materials of non-OFSP varieties is still stronger than for the OFSP varieties. Therefore, projects and programs that promote the production of OFSP should not ignore the importance of popular local varieties, such as New Polista, to the farmers. The finding that distance to source of quality planting materials reduces demand for such materials supports the need to decentralize multiplication and make it available locally and closer to the farmers and the finding that a number of varietal attributes affect the demand for quality planting materials implies the need to focus breeding on varietal attributes in addition to the agronomic attributes.