Improvement of Water Use Efficiency on Potato Production 3- Response yield and quality of potato plants to moisture deficit and planting method

Two field experiments were carried out at Mallawy Water Requirements Research station – El Minia, Governorate; Egypt Water Management Research Institute – NationalWaterResearchCenter during 2012 and 2013seasons. The present research was carried out to study the effect of water stress and planting methods on yield, saving water and quality for Potato crop (Solanum tuberosum L). A split plot design with three replicates was conducted. The main plots were assigned to  five irrigation treatments  traditional irrigation (the farmers practices), 100%, 90%, 80% and 70% of field capacity for potato crop and the sub plots into two  planting methods (furrow and beds). The treatments of irrigation were distributed at random in the main plots. While planting methods treatments were distributed at random in the sub–plots. Results indicat that irrigation regime significantly affected total yield in both seasons, where values of total yield/fed. were increased as water stress increased until 80% of field capacity then decreased with 70% of field capacity in both seasons. Also planting method was significantly affected this character in both seasons. The highest yield of potato was obtained with planting in beds and saving water about 14.42% compare to planting in furrow in both seasons. The obtained results in present study show that when the best method was used (irrigated potato until 80% of field capacity and planting in beds A₄b₂) the irrigation water is saved more than the normal planting in furrow (common method in region) by about 29.72% in both seasons. This treatment was the most superior treatments (from view point water and production) on this character. Starch content values were significantly increased as water stress was decreased where  the highest values of starch content (based on dry weight) were obtained when plants irrigated by conventional irrigation (72.820 and 74.400) in the first and second seasons, respectively. Planting method significantly affected this character in both seasons, where the highest values were obtained from plants which planting in beds in both seasons. The interactions between the studied factors significantly affected strach content in both seasons. Irrigation regime significantly affected the protein content in both seasons, where the highest value was obtained from plants which irrigated with conventional irrigation (6.958 and 7.035%) in the first and second seasoins, repectively. Irrigation regime significantly affected total soluble solids percentage (TSS) and dry matter content in both seasons , where they were increased with increasing water stress in both seasons, and the maximum values of (TSS) and dry matter content were recorded when plants grown at the lowest level of water supply i.e. irrigation at 70% depletion of available water. Irrigation regime was significantly affected the specific gravity (g/cm³) of potato in both seasons, where the specific gravity was increased significantly as watrer stress was increased. Planting methods significantly affected on this character the second season only. The higher values were obtained from plants which cultivated in beds 1.312 and 1.274 (g/cm³) in the first and second seasons, respectively. Irrigation regime significantly affected  nitrite concentration in both seasons where was increased with increasing water stress in both seasons results show that, when water stress increased, nitrite concentration was decreased. It could be recommended that irrigated potato crop until 80% of field capacity and planting in beds instead of planting in furrow to produce high yield and quality with less amount of water applied under El-Minia province conditions.