Physiological behavior of potato varieties (Solanum tuberosum L.) under drought conditions

In the Andean highland regions of Tiraque, Cochabamba, Bolivia in two consecutive years, six varieties of potatoes contrasting in their tolerance to drought were evaluated in semi-controlled conditions by using small containers suitable for planting and under a shed cover that served as protector from the rain. The aim was to identify physiological parameters in potatoes that are sensitive to drought and are associated with crop productivity. Three water schemes were applied: R0 = irrigation at field capacity (witness), R1 = drought at the beginning of tuber (early drought) and R2 = a month drought tuber initiation (late drought). It has been observed that the physiological parameters Diffusive Stomatal Resistance (DSR), transpiration, Leaf Water Potential (LWP) and Leaf Relative Water Content (LRWC), were highly variable among the varieties studied. Drough increased the DSR and reduced the DSR, transpiration and the LRWC of all varieties. In drought conditions, there is an inverse relationship between RDE and transpiration, DSR and LWP, and a direct relationship between LWP and LRWC. Of all the varieties studied, Luk'y stands out because it maintains a low transpiration and reduces its LRWC to a lesser extent. This behavoir expresses that its ability to regulate water is different from other varieties. The physiological mechanisms associated more with the potato crop yield are the DSR, transpiration and the LWP.