Transpiration and leaf growth of potato clones in response to soil water deficit

Abstract

Potato (Solanum tuberosum ssp. Tuberosum) crop is particularly susceptible to water defi cit because of its small and shallow root system. The fraction of transpirable soil water (FTSW) approach has been widely used in the evaluation of plant responses to water defi cit in different crops. The FTSW 34 threshold (when stomatal closure starts) is a trait of particular interest because it is an indicator of tolerance to water defi cit. The FTSW threshold for decline in transpiration and leaf growth was evaluated in a drying soil to identify potato clones tolerant to water defi cit. Two greenhouse experiments were carried out in pots, with three advanced clones and the cultivar Asterix. The FTSW, transpiration and leaf growth were measured on a daily basis, during the period of soil drying. FTSW was an effi cient method to separate potato clones with regard to their response to water defi cit. The advanced clones SMINIA 02106-11 and SMINIA 00017-6 are more tolerant to soil water defi cit than the cultivar Asterix, and the clone SMINIA 793101-3 is more tolerant only under high solar radiation.