A review of surface disorders in strawberry: insights and challenges

Strawberry ( Fragaria × ananassa Duch.) is a high-value crop grown for the fresh fruit market. An attractive appearance is a key quality factor but is often compromised by fruit-surface disorders. Common ones are water soaking, cracking, bronzing, albinism and dried calyx. This review summarizes our current understanding of the mechanistic bases of these disorders, their triggers and their effective mitigation strategies. Water soaking and cracking both require the formation of cuticular microcracks, which develop when the fruit cuticle fails under tensile strain during expansion growth. Formation of microcracks is aggravated by surface wetness and exposure to high relative humidity. Cracking manifests as visible splits that penetrate the underlying tissues, whereas water soaking originates from excessive water uptake through the pre-existing microcracks, resulting in translucent, water-logged areas on the fruit surface. Bronzing results from a range of causes, most commonly high temperature and ultraviolet stress, which damage epidermal tissues and induce repair responses that produce brownish or yellowish, desiccated surface patches. Albinism and dried calyx, by contrast, are associated with physiological and nutritional imbalances, including excessive vegetative vigor and impaired calcium transport under saline conditions, leading to poorly colored, soft fruit and necrotic sepals, respectively. Although these disorders differ in symptoms, they share common drivers related to environmental stress, tissue integrity, and mineral nutrition. Management therefore targets multiple leverage points, including reduced moisture exposure, moderation of thermal stress, optimized mineral nutrition, and the selection of genotypes with more resilient surface tissues. Better management of surface disorders in strawberry requires a more thorough understanding of their mechanistic bases. It is likely the ultimate solution will be an integrated approach that combines cultural measures and selective breeding.