Physiological basis of drought tolerance in potato grown under long-term water deficiency

Abstract

<span>Coping with water shortages without compromising tuber yield is a major<br /><span>challenge for potato (<span><em>Solanum tuberosum </em><span>L.) production in northern China. In this<br /><span>study, we used three potato cultivars with different sensitivities to drought to<br /><span>evaluate the effect of long-term drought stress on morphological and physiological<br /><span>characteristics under field conditions during three growing seasons (2009-2011).<br /><span>Our aim was to identify the specific drought tolerance traits of the potato cultivars<br /><span>to enable their cultivation in arid and semi-arid regions. Our results show that the<br /><span>drought-tolerant cultivars had higher tuber yields under conditions of drought due<br /><span>an increased number of tubers per hill and increased individual tuber weight.<br /><span>Compared with the drought-sensitive cultivar Neishu no. 7, the drought-tolerant<br /><span>cultivars Kexin no. 1 and Konyu no. 3 had stronger root systems and a higher<br /><span>capacity for water absorption at later developmental stages and a higher leaf<br /><span>relative water content, which conferred enhanced water retention under drought<br /><span>conditions. Moreover, the levels of superoxide radical and hydrogen peroxide were<br /><span>lower and the activities of antioxidative enzymes, including superoxide dismutase,<br /><span>peroxidase and catalase, were higher in the drought-tolerant cultivars under<br /><span>drought stress conditions. These combined characteristics allowed the cultivars to<br /><span>exhibit different levels of water deficiency. The above agro-morphological and<br /><span>physiological parameters could be used as a basis for breeding potato varieties with<br /><span>enhanced drought tolerance.</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span><br /><br class="Apple-interchange-newline" /></span></span></span>