PhD-ThesisThis study investigated the market orientation of round potato fanners in the southern highlands ofTanzania. A market oriented farmer, assumed to be a maximiser ofshort run profit, is expected to select varieties with higher profit potential and in accordance with market preferences and would allot more acreage to a more profitable crop than those needed for home consumption. Thus, this study sought to achieve the following objectives: to determine the market preferences for round potato varieties; to determine factors guiding farmers’ selections for varieties they produce; to analyse the profitability by varieties; and to analyse the market orientation of the round potato farmers. A sample of 510 farmers was obtained in Njombe, Mbeya Rural and Nkasi Districts. Preferences for round potato varieties was analysed by using a mini market survey of 155 respondents. The collected data was analysed by using both quantitative and qualitative approaches. Gross margin (GM) analysis, logistic regression and ANOVA models, and commercialisation index (CI) were adopted for data analysis. The overall results showed that red-skinned round potatoes were preferred to white/purple-skinned ones whereby consumers associated colour with dry matter content. Farmers’ criteria for variety selection included seed tuber availability, market demand, price, and common practices. Econometric results indicated that gender (p<0.01), education level (p<0.05), prices of previous season (p<0.01), location (p<0.01) and extension services (p<0.01) influenced farmers’ selection of varieties. Farmers who consulted the extension officers were 2.6 times more likely to choose varieties in accordance with the market preferences than others. The ANOVA model indicated that there was significant difference in profitability among varieties. Kagiri was the highest profitable variety with mean GM ofTZS 794 889 per acre followed by Tigoni (TZS 618 167), Kikondo (TZS 484 900), and Arka (TZS 377 743). The proportion of land allotted for the crop ranged from 20% of total land under cultivation at Nkasi to 67% in Mbeya Rural. Furthermore, CI of 88% showed that round potato production was highly market oriented. Based on key findings, the study recommended that plant breeders should include consumer preferences as part of their breeding programme.