Transpiration Efficiency of Some Potato Genotypes under Drought

Abstract

Potato (Solanum tuberosum L.) is the third most consumed food crop after rice and wheat in the world. It is a short-duration crop, suitable for growing in a wide range of environments, but abiotic factors can limit potato production, and drought is the main one. Therefore, managing drought stress is of utmost importance under climate change conditions. Potato as a drought-sensitive crop needs choice of suitable genotypes for dry environments. In this study, transpiration efficiency (TE), soil water conservation and drought tolerance were analysed for potato genotypes from different origins. Three glasshouse experiments under different Vapor Pressure Deficit (VPD) conditions with water-stressed (WS) and well-watered (WW) plants resulted in significantly different total amounts of transpiration among the genotypes and water supply levels. Transpiration in WS plants was the same as with WW plants up to a specific threshold “Fraction of Transpirable Soil Water” (FTSW) and then sharply decreased in response to soil drying. Genotypes showed a substantial variation in FTSW thresholds (0.19 to 0.36 FTSW) under low VPD condition, which narrowed down (0.19 to 0.29) when air humidity was lower. Furthermore, we observed hardly any relationships between TE and FTSW threshold (r = 0.125) or TE and water saving (r = 0.031). Our results provide insights into genotypic interactions with VPD on FTSW threshold and TE under dry-down conditions in potato.