Impact of arid climate on ecophysiological characteristics and water utilization patterns of two olive cultivars (Olea europaea L.) in the Mediterranean dryland: a case study of 'Chemlali Sfax' and 'Koroneiki'

In olive-growing regions, climate change exacerbates challenges like high temperatures and water scarcity, necessitating a deeper understanding of its impact on olive trees behaviour to cope with drought. This study assesses the ecophysiological performance of 12-year-old olive trees 'Chemlali Sfax' (local) and 'Koroneiki' (Greek) and drought response mechanisms for developing agronomic strategies that ensure sustainable yields despite adverse climatic conditions in the Mediterranean region (Tunisia). Leaf water content declined from February, with 'Chemlali Sfax' and 'Koroneiki' maintaining higher content (59%) in June 2012. 'Koroneiki' exhibited significantly reduced relative water content (48.09%), leaf area (396.82 mm(2)), stomatal (346.59 ST/mm(2)), and trichomic densities (135.66 TR/mm(2)) compared to 'Chemlali Sfax'. Soil moisture in the 40-80 cm horizon was higher in April, with 'Koroneiki' reaching 5.40% compared to 'Chemlali Sfax' at 4.42%. 'Chemlali Sfax' significantly outperformed 'Koroneiki' in yield, yielding 1129.2 kg/ha compared to 956.9 kg/ha during the 2011-2012 period. Despite these differences, both cultivars showed promising productivity potential under arid, rain-fed conditions, with an average water utilization of 0.8 kg/m(3). 'Chemlali Sfax' and 'Koroneiki' demonstrated favourable adaptability and yield stability in arid conditions, suggesting its potential suitability for cultivation in such environments. Future research directions include exploring the effects of planting both cultivars at identical densities and combinations on olive oil and fruit qualities, as well as exploring additional ecophysiological parameters to enhance understanding of olive tree responses to water stress and drought tolerance mechanisms.