Effect of water stress on quantity traits of potato traditional cultivars and advanced clone

In order to identify the effect of water stress on potato traditional cultivars and advanced clone growth this experiment was carried out under field conditions as Split-plot design based on Randomized Complete Block Design with three replications in Ardabil Agriculture and Natural Resources Research Station during 2015. Main plots included three irrigation levels: complete irrigation, mild and severe water stress and sub-plots included 5 potato cultivars: Agria, Spirit, Marfona, Luca, Hermes and 397008-9 promising clone. Results showed that in spite of the effect of water stress on marketable tuber number per plant, other studied traits such as tuber weight per plant, marketable tuber weight per plant, total tuber yield and marketable tuber yield were influenced by irrigation and cultivar treatments. Luca and Marfona produced the highest marketable tuber weight per plant and marketable tuber number per plant, respectively and also the 397008-9 promising clone had the most highest total tuber yield and tuber weight per plant due to genetic diversity. There were no significant interaction effect between cultivars × irrigation levels on any traits. Because of no significant difference between complete irrigation and mild water stress treatments and also economic importance of tuber yield for farmers, It seems that replacement of complete irrigation by mild water stress, not only will lead to relative maintaining water resources, but also will produce good marketable tuber yield (In accordance with the cultivar).