ASHS 2025 Conference

Blueberry (Vaccinium spp.) texture is a key trait in breeding programs primarily due to its influence on consumer acceptance, machine harvestability, transportability, shelf-life, and overall quality. Variations in firmness have been extensively studied on southern highbush (SHB; Vaccinium corymbosum L.), with little reported on rabbiteye (RE; Vaccinium virgatum) genotypes. Various texture instruments, including FruitFirm1000, FirmTech II, and TA.XT2 Plus texture analyzers, are used, but not all assess multiple mechanical parameters on blueberry fruit. Initial firmness evaluations on 17 RE and SHB genotypes using a FruitFirm1000 identified genotype-specific variations over six weeks of storage (4 °C, 85% relative humidity). At harvest (day 0), ‘Titan’ (RE) had the highest firmness (287 g.mm-1), while ‘MS1110R’ (RE) had the lowest (152 g.mm-1). After 4 weeks in storage (day 28), RE genotypes of ‘Titan’, ‘Vernon’, ‘T-3075’, and SHB ‘Legacy’ maintained high firmness (˃200 g.mm-1). While ‘Alapaha’ (RE), ‘New Hanover’(SHB), and ‘MS1110R’ (RE) did not retain firmness (˂150 g.mm-1). Texture is a complex and multi-component trait; a single firmness measurement cannot comprehensively capture all attributes influencing blueberry texture variations. To further understand blueberry mechanical parameters, our current study utilizes a TA.XT2Plus texture analyzer equipped with 2 mm needle and 2 mm flat probe. The needle probe will measure force parameters across different blueberry tissues: epidermis (Fep), hypoderm (Fh), parenchyma (Fp), and inner pulp (Finner). The 2 mm flat probe will measure mechanical parameters derived from force-distance curves, which relates to skin elasticity, internal firmness, graininess/grittiness, skin strength, and stiffness (Young’s modulus). Ten blueberry genotypes (7 RE and 3 SHB) representing distinct crisp/high, medium, and low firmness levels will be harvested and stored at 4 °C and 85% relative humidity. Texture measurements will be taken at two postharvest timepoints, day 0 and 14. By integrating advanced texture analysis (TA.XT2Plus) compared to FruitFirm1000, a comprehensive understanding of firmness variability and texture changes in RE compared to SHB blueberries will be obtained. The advanced textural assessment will enable data-driven insights to inform breeding selections for improved texture in fresh-market cultivars.