Approaches to enhancing water productivity in potato

Potato produces more food per unit of water than any other major crop. For every cubic meter of water, potato produces highest dietary energy (5600 Kcal)compared to maize (3860 Kcal), wheat (2300 Kcal) and rice (2000 Kcal).Modern day potato varieties are sensitive to moisture stress and need frequent irrigation. In Indian conditions, potato crop needs 400600 mm water depending on soil types, length of growing season, and duration of crop and method of irrigation.The target of "more crop per drop" can only be achieved by increasing WUE. Potato yield is more likely to be source limited instead of sink during tuber bulking because water availability is a key production management factor and interaction between water and nitrogen influence potato yield mainly through affecting source capacity via the net photosynthetic rate, total leaf area and leaf life span. To develop water use efficient genotype identification and selection of a drought resistance genotype which uses water efficiently under to produce more biomass and better partitioning towards sink (tuber) is the prerequisite for future breeding programs. There is a need to develop a reliable technology that can measure plant WUE efficiently by using quantifiable stress indicators. Adequate RWC for longer period, decrease in meristematic activity, increased root: shoot ratio is some key screening feature for a water use efficient genotype. In parallel, identification of key molecules involved in signaling mechanism, development of new biotechnological and bioinformatics tools may help us to dissect out the whole pathway.