Impact of carbon deprivation on apple fruit quality during cold storage

Fruit quality is built on complex traits such as taste, texture, colours and aromas, developed during fruit maturation and cold storage. The genetic, molecular and ecophysiological bases of these traits are still mainly unknown.
Apple fruit development is characterized by a complex network of sink-source interactions due to concomitant vegetative and bourse shoots development during the growing season. Several studies are pointing out a possible direct relationship between dry mater accumulation and high quality texture (1, 2). In order to study the impact of trophic competitions on fruit quality, the sink-source equilibrium was modulated at the level of the fruit bearing branch or the inflorescence by defoliation treatments.
The experiments were carried out on four apple varieties with contrasting sensory phenotypes. Apple quality was investigated with sensory, morphometric, mechanical, biochemical and transcriptomic analyses. The impact on fruit development and quality is depending on the timing of the defoliation treatment and on the variety. If late defoliation did not impact much fruit quality, data suggest an important role of bourse leaves in early stages of fruit development. Fruits transcriptome analyses also revealed a differential stress response to cold storage, probably due to increased sunlight exposition which depend on tree architecture. A drastic effect was observed on developing buds with a total fall during the next winter.
(1) Palmer et al., 2010 Journal of the Science of Food and Agriculture 90(15).
(2) Saei et al., 2011 Scientia Horticulturae 130(1).