Central Potato Research Institute, Simla
To find out a physiological tool to serve as an index of drought resistance, the response of potato to water stress was studied in ten genotypes grown in earthenware pots. Water stress was imposed at tuber initiation stage by withholding watering for a week.
Water saturation deficit in leaves was found to be significantly correlated with tuber weight (r=-0.889**) and tuber number (r=-0.870**) under stress conditions, whereas in non-stressed plants water saturation deficit correlated with tuber weight (r=-0.793**) but not with tuber number. Stomatal conductance negatively correlated with tuber weight (r=-0.961***) and with tuber number (r=-0.887**) under stress conditions which suggests that yield is reduced by loss in leaf water content rather than stomatal closure. No significant correlation existed between stomatal conductance and tuber weight or number in non-stressed plants. Proline accumulation in leaves showed a significant negative correlation with tuber weight (r=-0.792*) and tuber number (r=-0.902**) in stressed plants. In non stressed plants proline accumulation In leaves correlated negatively (r=-0.752*) with tuber number. The study indicated that stomatal conductance was a better parameter to serve as an index for drought resistance than water saturation deficit and proline content in leaves of potato.
