Sunburn in Grapes: A Review

Area of Science:

• Viticulture and Plant Physiology
• Agricultural Science
• Fruit Quality Research

Background:

• Sunburn negatively impacts grape visual and organoleptic properties, decreasing commercial value and yield.
• Sunburn manifests as sunburn browning (SB) or sunburn necrosis (SN), influenced by damage severity and contributing factors.
• Excessive photosynthetically active radiation (PAR), UV radiation, and high temperatures, often worsened by water deficit, trigger sunburn.

Purpose of the Study:

• To review current knowledge on grape sunburn, comparing it with findings from other fruit species.
• To analyze factors influencing the incidence and severity of sunburn in grapes.
• To discuss the biochemical responses of grapes to sunburn and explore potential mitigation strategies.

Main Methods:

• Comprehensive literature review synthesizing existing research on grape sunburn.
• Comparative analysis of grape sunburn with related phenomena in other fruits.
• Discussion of contributing environmental factors, physiological responses, and management techniques.

Main Results:

• Grapes exhibit defense mechanisms against sunburn, including antioxidant activation, synthesis of optical screening compounds, heat-shock proteins, and morphological adaptations.
• Sunburn severity is modulated by a complex interplay of radiation, temperature, and water status.
• Various factors contribute to the appearance and degree of sunburn, necessitating a multifaceted understanding.

Conclusions:

• Understanding grape sunburn's physiological and biochemical underpinnings is crucial for effective management.
• Further research is needed to refine mitigation strategies and enhance grape resilience to sunburn.
• This review provides a foundation for future investigations into preventing and managing sunburn in viticulture.