Sesame (Sesumum I.) crop is one of the cash crops exported from Ethiopia to Europe and Asia that contributed to the country GDP. The main objective of this study was to evaluate the water use efficiency (WUE) under full and deficit irrigated sesame crop in wereda Kafta-Humera, Tigrai-Ethiopia. Sesame crop production was particularly related to the summer (Kiremt rainfall). But due to a variation in rainfall distribution in the area, sesame crop production that was harvested by farmers decreased. To solve this problem and to single out the irrigation water application level that could let the farmers earn high production, field based research is needed. Field experimental plots with three replications were conducted. The leaf area index (LAI), biomass and grain yield were measured at the field level. Moreover, AquaCrop model was used to simulate the biomass, grain and transpiration rate. Cropwat-8 model was used to compute irrigation water requirement and scheduling. The experimental results indicated that the average grain yield earned from treatment levels 1 and 2, 3 and 4 were recorded as 11.23, 8.98, 7.17 and 4.70 quintal per hectare respectively. The water use efficiency (WUE) for grain yield exhibit higher Grain water use efficiency of 1.307 kg/m3 was observed under 90% irrigation application (Tr-2). Whereas, 1.299 kg/m3, 1.194 kg/m3 and 1.071 kg/m3 were observed under 100% application (Tr-1), 80% application (Tr-3) and 70% application (Tr-4) respectively . In case of Biomass water use efficiency, the higher Biomass water use efficiency was earned under Tr-3 (80%) irrigation application with value of 3.19 kg/m3. Whereas, biomass water use efficiency of 3.18 kg/m3, 3.08 kg/m3 and 2.66 kg/m3 were exhibited under the deficit irrigation Tr-2, Tr-4 and Tr-1 respectively.

Keywords: Full and deficit irrigation, Water use efficiency, AquaCrop)