Optimum Irrigation Events for Potato Cultivar Agria

This research was conducted to find optimum irrigation events for potato (cv. Agria) based on potato yield and water use efficiency (WUE) under Ekbatan, Iran, climate condition with a mean annual relative humidity of 51% and rainfall of 200 mm. Results revealed that the highest (28.47±3.58 t) and lowest (24.58±2.05 t) yields were produced by partial with 16 and full irrigation with 18 events, respectively. These originated from insensitiveness of initial vegetative stage of potato to partial irrigation. On the other hand by 18 events with 13408±58 m 3 ha -1 water was applied to the experimental plots. While water requirement of potato is 6640 m 3 ha -1 and it seems extra application of water caused a decrease in yield. It was found that the highest (2.36±0.35 kg m -3 ) and lowest (1.84±0.18 kg m -3 ) WUE produced by partial with 16 and full irrigation with 18 events, as well. Since initial vegetative stage of potato is not sensitive to water deficit, partial irrigation did not cause a decrease in yield but also increased WUE relative to full irrigation. To relate crop yield to water applied, a water production function was developed by multiple regressions analysis. Applying 16 irrigation events caused a yield increase as 13.21±4.05% and water saving up to 9.88±2.35% relative to 18 irrigation events. Therefore, it is recommended that potato cultivar Agria should be irrigated with 16 irrigation events to achieve the optimum yield and WUE.