Light exposure affects fruit quality in different strawberry cultivars under field conditions

Abstract Strawberry ( Fragaria x ananassa Duch.) fruits are highly appreciated worldwide because of their flavour and their content on healthy-related compounds. Most of these compounds have antioxidant properties and photo-protective activities involved in plant response against environmental constrains, including light availability. Thus, fruit quality might be affected by variation in environmental factors such as light conditions. A field experiment, performed under conventional cropping conditions, was designed for assessing the effects of the light exposure level of fruits on fruit quality parameters in four strawberry cultivars (‘Sabrina’, ‘Fortuna’, ‘Splendor’ and ‘Primoris’) during a cropping season. To assess to what extent strawberry genotypes are able to modulate their fruit quality traits in response to light conditions, a plasticity index was calculated for a quantitative estimation of the amount of phenotypic change induced by the environment (i.e. light-exposure) on the different strawberry cultivars. Results showed that proportion of exposed fruits compared to non-exposed ones was similar in all cultivars despite their differences in canopy size. This was achieved by modulating peduncle length: the higher the canopy size, the higher the peduncle length. This work also demonstrates that light incidence influences strawberry fruit quality - flavour and antioxidant content- and that the responsiveness to light conditions, estimated by the plasticity index, of strawberry fruits is genotype dependent. These results are suggesting differences among cultivars in the ability of adapting to variable light environments, and their significance in a breeding context and from an applied point of view is discussed.