Exploring the Impact of High-Temperature Stress on Physiological, Anatomical, Molecular, Productive, and Quality Parameters in Diverse Olive Cultivars

Olive (Olea europaea L.) is one of the most important horticultural crops in Saudi Arabia. High temperatures are typical in most regions during the summer season. This study explored the effect of high temperatures on diverse olive cultivars (Manzanillo, Chemlali, and Picual) grown in three different geographical locations in Saudi Arabia (Sakaka, Basita, and Al-Qurayyat). Sakaka region was classified as a hot region, while the Basita and Al-Qurayyat regions were characterized by relatively mild or low temperatures. Genotypic components were assessed by studying Amplified Fragment Length Polymorphism (AFLP) molecular markers and physiological, anatomical, productive, and oil quality parameters. The evaluated genotypes displayed considerable variation across the three studied locations. Picual exhibited more heat tolerance, followed by Chemlali and Manzanillo. The high temperature in Sakaka negatively impacted critical characteristics related to olive growth, production, and quality. Results revealed that linoleic acid, oil acidity, total phenols, upper epidermis, palisade tissue, vascular bundle area, and mesophyll were the most appropriate parameters for predicting the impact of high temperatures. These traits were highly correlated with Sakaka and were highly and significantly associated with all the studied markers. Also, significant interactions between locations and genotypes showed that the means for most of the studied traits were the highest in Basita region.