Developing resilience to heat stress in fruit orchards: A comprehensive review

Heat stress is emerging as a major constraint in fruit production across the globe, driven by rising temperatures and increasing climate variability. Fruit crops are particularly vulnerable to high temperatures, which adversely affect physiological processes, flowering, fruit set, quality and yield. Developing resilience is hindered by factors such as the complex genetic basis of heat tolerance, limited availability of heat-resilient cultivars and economic or infrastructural limitations faced by growers, particularly in resource-constrained regions. Developing resilience to heat stress has become critical for sustaining orchard productivity, especially in tropical and subtropical regions. This review synthesizes current knowledge on the physiological, biochemical and molecular responses of fruit crops to heat stress, while also examining practical orchard management strategies-including shading nets, mulching, regulated deficit irrigation and anti-transpirants as well as the role of exogenous applications of plant growth regulators and nutrients in mitigating heat-induced damage, with emerging biological solutions such as microbial inoculants and biostimulants providing eco-friendly alternatives for enhancing plant tolerance. Furthermore, advancements in breeding-through marker-assisted selection, genomics and gene editing technologies are accelerating the development of heat-resilient cultivars. An integrated approach combining technological, agronomic and genetic tools is essential to build long-term heat resilience in fruit orchards. The paper concludes by emphasizing the need for region-specific interventions, farmer-centric research and policy support to promote climate-smart horticulture.