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Abstract

Tropical root and tuber crops such as cocoyam (Colocasia esculenta (L.)) are important for food security and livelihoods and yet neglected in climate change impact studies and large-scale crop improvement programs. The aim of this study was to apply the maximum entropy modelling approach to assess production potential for the orphan crop cocoyam under current and projected climatic conditions by 2050 and 2070 in Zimbabwe. A robust model fit was achieved (AUC > 0.9) with variable importance showing that precipitation-related factors were most important in determining the suitability of cocoyam. About 4.3% of the country is suitable for cocoyam production in Zimbabwe under current climatic conditions with the most suitable areas in eastern districts of Chipinge, Chimanimani, Mutare, Mutasa, Nyanga and Makoni. By 2050, model means project a decrease of 6%, 9%, 10% and 15% under RCP2.6, RCP4.5, RCP6.0 and RCP8.5, respectively. More drastic decreases are projected by 2070 with almost a quarter (23%) of the current suitable areas having lost their suitability for cocoyam production. There is a general model agreement in the direction of impacts except for RCP2.6 where CCSM4 model projects increases in suitability for cocoyam in the country while other models project decreases. We find that regulating canopy microclimate variation increases potential for cocoyam production under climate change and can be implemented to ensure resilience of cocoyam production systems. Therefore, stabilizing or improving orphan crops systems will substantially contribute to local food security and reduction of malnutrition especially during the lean season.