Optimization of in vitro propagation of blueberry: influence of plant growth regulators and medium components on multiplication and rooting

Blueberry (Vaccinium sp.) is a fruit with significant economic value, where propagation efficiency directly affects seedling availability and production scale. This study aimed to optimize the In vitro propagation process for three blueberry cultivars (Bluegem, Climax, and Woodard), specifically by enhancing shoot multiplication rates, ensuring uniformity, and improving rooting efficiency and ex vitro survival, while also assessing critical physiological health indicators, focusing on both the multiplication and rooting phases. During shoot multiplication, stem segments were cultured on Woody Plant Medium (WPM) supplemented with varying concentrations of 2-isopentenyladenine (2-ip) and adenine sulfate. The combination of 2.5 mg L⁻¹ 2-ip with 10 mg L⁻¹ adenine sulfate resulted in the highest number of shoots for Bluegem and Climax, whereas 2.5 mg L⁻¹ 2-ip and 20 mg L⁻¹ adenine sulfate were most effective for Woodard. Enhanced shoot proliferation and uniformity were observed across all cultivars, facilitating subsequent micropropagation steps. In the rooting phase, microcuttings were initially inoculated with indole-3-butyric acid (IBA) and then transferred to WPM medium at different concentrations (0–100%), with or without activated charcoal. Rooting responses were cultivar-dependent: Bluegem exhibited optimal rooting at 75% WPM, whereas activated charcoal was beneficial only for Climax. These protocols resulted in increased rooting and higher ex vitro survival rates, supporting successful acclimatization. Overall, the use of targeted growth regulators and optimized medium components at each propagation stage improved the multiplication rates, rooting efficiency, and acclimatization of blueberry cultivars under In vitro conditions. Targeted adjustment of growth regulators and medium strength improved both multiplication and rooting performance in blueberry micropropagation.