Linking anatomy and physiology of almond to irrigation strategies: Towards standardized thresholds and decision-support tools for water-limited environments

Almond ( Prunus dulcis (Mill.) D.A. Webb) is one of the most important nut crops cultivated in arid and semi-arid regions, where water availability is a key factor determining yield and nut quality. Its domestication in dry environments has favoured traits such as deep rooting and early phenology, which confer a moderate tolerance to drought. However, under prolonged or severe water stress, these adaptations become insufficient, leading to declines in yield. Understanding the balance between tolerance and vulnerability is therefore essential for developing irrigation strategies that ensure yield stability, nut quality and long-term orchard resilience under climatic conditions and modern cultivation systems increasingly dependent on irrigation. This review provides an integrative overview of almond’s anatomical and ecophysiological responses to water availability, emphasizing key physiological indicators, such as water potential, stomatal conductance, and leaf temperature, as tools to guide irrigation management. The reliability of these variables depends on environmental conditions, phenological stages, and cultivar-specific traits, which complicates the definition of universal thresholds. By integrating anatomical and physiological evidence with recent advances in monitoring technologies, this review aims to support the development of standardized, adaptive irrigation protocols that enhance water use efficiency of almond trees while preserving yield and nut quality. Understanding cultivar adaptation and physiological thresholds is critical to ensure resilient almond production under increasing climate and water challenges.