Effects of Cultivation Systems and Mulching on Yield and Fruit Quality of Highbush Blueberry (Vaccinium corymbosum L.)

Highbush blueberry (Vaccinium corymbosum L.) is a major berry crop valued for its nutritional and bioactive properties. This study evaluated the influence of cultivation systems and genotypes on fruit quality and antioxidant potential in a two-factorial field experiment (four cultivars × four systems). ‘Sunrise’, ‘Draper’, ‘Ozark Blue’, and ‘Aurora’ were assessed for physicochemical traits, total polyphenols (TPC), vitamin C, nitrates, and antioxidant capacity (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolourisation (ABTS•+), 2,2-diphenyl-1-picrylhydrazyl (DPPH•), and ferric-reducing antioxidant power (FRAP))). The maximum fruit weight was recorded in cv. Aurora grew under the raised-bed with agrotextile system (353 g per 100 berries), while Draper produced the smallest fruits (227 g). Soluble solids ranged from 12.2 to 16.9 °Brix, acidity from 0.53 to 0.97 g/100 g FW, and TPC from 318 to 544 mg/100 g FW. Agrotextile treatments stabilised microclimate and reduced stress, resulting in lower ABTS (17.9 vs. 24.0), DPPH (19.8 vs. 22.3), and FRAP (11.6 vs. 13.9 mmol TE/100 g FW) values, indicating stronger radical scavenging activity. Ozark showed the highest TPC, vitamin C (123 mg/1000 g FW), and firmness (420 g/mm), whereas Aurora and Sunrise had brighter fruits (L = 37.6–36.1). Nitrate concentrations remained low (42–68 mg/1000 g FW). Genotype × system interactions significantly influenced secondary metabolite synthesis and stress adaptation. Raised beds with agrotextile improved fresh-market quality, while traditional systems favoured storage stability, providing practical, sustainable cultivation guidelines.