Agro-physiological responses of the pistachio (Pistacia vera L., cv. Mateur) to partial root drying (PRD) irrigation

Purpose: Water irrigation regimes strongly influence the agrophysiological parameters in pistachio. This study aims to investigate the impact of the partial root drying on the yield, vegetative growth, physiological parameters, water status and biochemical traits of the pistachio cv. Mateur budded on P. atlantica rootstocks during the growing season (۲۰۲۱). Research Method: The agro-physiological responses of the pistachio trees located in the experimental orchard of the Regional Center of Agriculture Research (CRRA, Sidi Bouzid, Tunisia), were studied. Three water treatments were applied; T۰: ۱۰۰% Partial root drying (PRD) during all the season, T۱; ۷۵% PRD during all the season and T۲; ۵۰% PRD during all the growing season. The leaf gas exchange parameters were determined using a portable photosynthesis system (CI-۳۴۰ handheld photosynthesis system, USA). Findings: Results showed the stomatal conductance (gS) of pistachio leaves ranged from ۳۲۰ to ۷۶۰ mmol H۲O m-۲s-۱ in the ۱۰۰% PRD treatment whereas the water regimes ۷۵% PRD and ۵۰% PRD presented a clear decrease in this parameter. The proline and the soluble sugar content reached its maximum value (۲.۱۰ μmol g−۱ FW and ۲۷۵.۶۰ μg g−۱ FW, respectively) under the ۵۰ % PRD treatment during the month of August. Research limitations: No limitations were found. Originality/Value: The ۷۵% PRD treatment was the most efficient as it did not show significant differences with the ۱۰۰% PRD treatment while ۲۵% of the irrigation water was saved. The partial root drying strategy can be used in pistachio orchards under semi-arid conditions.

Keywords:

Gas exchange , Pistachio , Relative Water Content , Stomatal Conductance