Growth and physiological responses of various pomegranate (Punica granatum L.) cultivars to induced drought stress

The purpose of this study was to evaluate the drought response of eleven pomegranate cultivars during two consecutive years (2020–2021) by assessing their response to severe water stress. Irrigation treatments consisted of a control treatment irrigated at 100% of crop evapotranspiration ETc (CT) and a water stress treatment irrigated at 50% ETc (ST). The measurements concerned the vegetative and physiological properties of the pomegranate trees under both treatments. Results showed that all traits were affected by water stress, except the stomatal area index. Since the first year of the experiment, a higher decrease in shoot length was observed in ‘Gjeibi’ (78%), ‘Sefri’ (64%) and ‘Mollar Osin Hueso’ (38%). For the stomatal conductance, the most affected cultivars were ‘Grenade rouge’, ‘Gordo de Jativa’; ‘Sefri’ and ‘Ounk Hmam’, while ‘Grenade Jaune’, ‘Mollar Osin Hueso’, ‘Bzou’ and ‘Zheri Precoce’ were less affected. This last cultivar was the only one affected in stomatal density by rate of 37% in 2020. The effects of water stress on leaves’ chlorophyll, proline and cuticular wax contents varied among the cultivars and the years of the experiment. The multivariate analyses based on the stability indexes of the observed traits highlighted five distinctive groups among the studied cultivars in terms of the water stress response. The highest impact on discrimination between the cultivars in response to water stress was attributed to the stability indexes of shoot length, stomatal area, stomatal area index and chlorophyll-a content. © The Author(s) under exclusive licence to Society for Plant Research 2023.