Evaluation of the effect of leaf removal timing in Chardonnay berries with regards to fruit composition and sunburn incidence

Sunburn is a physiological disorder that leads to yield and quality losses in a range of fruits such as grapes and apples. It affects the visual appearance and the composition of the fruit, leading to irreversible changes and ultimately, cell death in extreme situations. Sunburn is caused by a combination of excessive radiation and temperature that lead to photo and thermal stress, the formation of reactive oxygen species and oxidative stress.

A series of factors, such as environmental conditions, grape variety and development stage modulate the final amount of damage. In turn, berries have evolved a series of mechanisms to protect themselves that are dependent on developmental stage. Secondary metabolites such as the carotenoids, polyphenols and even the aroma compounds can act as antioxidants and light screens, however, the ability to upregulate their production depends on ripening stage.

This project aimed to evaluate the changes in secondary metabolism generated by varying degrees of sunburn damage in Chardonnay grapes, and how exposure of berries through defoliation at two different stages in development could modulate sunburn intensity.

Video of the seminar held during Macrowine virtual (June 23-30, 2021)