Assessing predictability of post-storage texture and appearance characteristics in blueberry at breeding population level

The shelf-life of blueberry (Vaccinium corymbosum L.) fruits depends on changes in multiple fruit characteristics during storage, including texture, appearance of wrinkles and mold, and loss of water. These changes result in softening, decay, and change in flavor, which can negatively affect consumer acceptance. Therefore, understanding how breeders can select for new cultivars with extended shelf-life is crucial. In this study, 20 mechanical texture parameters and four fruit appearance traits (fruit weight, fruit scar diameter, fruit height and wrinkle) were measured at harvest and six weeks post-storage in two very large (N>2000) collections of northern and southern highbush blueberry (NHB, SHB, respectively) genotypes. The study is the first to assess shelf-life at the scale resembling the number, genetic structure and diversity of populations used in blueberry breeding programs. The results highlighted that post-storage changes are positively correlated with initial texture. The low storage temperature for SHB best explained a notable lower rate of changes for all parameters. Correlation analysis indicated that three main texture components representing the Young Modulus parameters (YMs), ‘Distance to Maximum Force’ (DFM) and ‘Mean Internal Firmness’ (MIF) contributed to blueberry texture. YMs and DFM likely represent textural characteristics of the external fruit structural components. Also, texture parameters YMs and DFM explained most of the phenotypic changes observed between harvest and post-storage, suggesting that changes during storage largely occurs in the more external layers of the berry. Changes for parameters correlated to size were highly predictable, while most of the texture parameters had a low to moderate predictability. The contribution of fruit chemistry parameters to predict texture and appearance traits at harvest and post-storage was very limited or not significant. The rate of water loss and appearance of wrinkles was higher in small size berries and was not affected by the size of the stem scar. Overall, selecting for high YMs, DFM, F1mm (Force at 1 mm), Maximum Force (FM), and large size at harvest can contribute to select berries with better mechanical texture and appearance in post-storage.