Despite the large area coverage of cereals in Ethiopia, their national productivity is much below the average of African and world yield productivity. Analyzing the yield gap, i.e. the difference between yield potential (Yp) and the actual yield (Ya) is essential to explore intervention options that can minimize the yield gap. Therefore, this paper aims to estimate the yield gap and map its spatial variation for bread wheat and malt barley production in the southeastern parts of Ethiopia. The process-based Decision Support System for Agro-technology Transfer (DSSATv4.7.5) crop model was calibrated for 2 wheat varieties (Hidase and Ogolcho) and one barley variety (Ibone) and used to estimate the potential yield. Potential yield was estimated for each selected reference weather station, and compared with the corresponding (Ya) s achieved by farmers averaged at district level to estimate the yield gap. The model simulated the highest potential yields of 7 and 6.3 t/ha, respectively for Hidase and Ogolcho varieties at Dinsho site. In contrast, the lowest yield was simulated at Ziway-Dugda (4.9 t/ha) for Hidase and at Merti (4.4 t/ha) for Ogolcho varieties. Moreover, the highest yield gap (78%) was determined at Amigna and the lowest yield gap (26%) was determined at Lemuna Bilbilo district for malt barley. Generally, the analysis revealed that there are high yield gaps and its spatial variation across study sites is also high for both crops.

Keywords: Bread Wheat; Crop model; Malt Barley; Model calibration; Southeastern Ethiopia; Yield gap