Comparative evaluation of micropropagated and conventionally propagated thornless blackberry (Rubus spp.) cultivars: Agronomic performance, fruit biochemical quality, and functional food potential

Abstract

Background: Blackberry (Rubus spp.) is a valuable functional food crop rich in phenolics, anthocyanins, flavonoids, vitamin C, and other bioactive compounds. Although micropropagation enables rapid production of uniform planting material, its effects on multi-year field performance and fruit biochemical quality remain insufficiently documented under specific agroecological conditions. Objective: This study compared micropropagated (MP) and conventionally propagated (CP) plants of four thornless blackberry cultivars (‘Doyle’, ‘Loch Ness’, ‘Natchez’, and ‘Freedom’) under Armenian conditions, focusing on field performance, disease incidence, and fruit biochemical quality relevant to functional food applications. Methods: MP plants were produced through nodal explant culture, shoot multiplication, IBA-mediated rooting, and greenhouse acclimatization. Field trials were established in 2021 using a randomized complete block design. During 2022–2023, plant survival, growth, flowering, yield, fruit weight, and disease incidence were evaluated. Fruit quality was assessed for vitamin C, total phenolic content (TPC), anthocyanins, flavonoids, and DPPH antioxidant capacity. Results: MP plants generally showed higher survival, vegetative growth, flowering, yield, fruit weight, and lower disease incidence than CP plants. In 2023, MP ‘Loch Ness’ produced 17.4 stems plant⁻¹, while disease incidence was 7.5–11.3% in MP versus 18.1–26.5% in CP plants. MP fruits contained higher levels of bioactive compounds, with the highest values in ‘Natchez’: vitamin C, 31.4 mg/100 g FW; TPC, 412.7 mg GAE/100 g FW; anthocyanins, 159.2 mg C3G/100 g FW; and flavonoids, 62.1 mg CE/100 g FW. DPPH antioxidant capacity was approximately 32% higher in MP fruits across all cultivars. Conclusion: Micropropagation improved field performance, phytosanitary status, and fruit biochemical quality of the evaluated thornless blackberry cultivars. It therefore offers a promising strategy for standardized production of high-quality blackberry planting material and fruit with functional food potential. Novelty of the study։ This study provides a multi-season, cultivar-specific comparison of micropropagated and conventionally propagated thornless blackberry plants under identical open-field conditions in Armenia. By combining agronomic performance, disease incidence, and fruit biochemical traits, it evaluates how propagation method influences both field productivity and the accumulation of selected bioactive compounds. Keywords: Blackberry; Rubus spp.; Micropropagation; Bioactive compounds; Antioxidant activity; Functional food