GROWTH OF MICROPROPAGATED BLUEBERRY UNDER DIFFERENT GA3 CONCENTRATIONS

Abstract

The work aimed to evaluate the growth of micropropagated blueberry plants, cultivar ‘Georgiagem’, using different concentrations of GA3. It used plantmax® + vermiculite as substrate. A completely randomized design in a 4×3 factorial arrangement with four concentrations of regulators and three evaluation periods – 0, 30 or 60 days was used. Four replicates of five plants each were utilized. The concentrations of regulators were: 0, 50, 100 or 150 mg/L of GA3, and they were applied every two weeks. At 0, 30 and 60 days after experiment installation plant height, number and mean length of shoots were measured. At 60 days the fresh and dry biomass of both aerial part and root were assessed. Plant height and mean shoots length were affected by the GA3 dose x time of application. The number of shoots was affected only in relation to the time of application and not by concentrations of GA3. Higher concentrations of regulator promoted superior mean length of shoots at 60 days (150 mg/L – 13.9 cm, 100 mg/L – 11.1 cm and 50 mg/L of GA3 – 11.3 cm). There was no significative effect in fresh and dry aerial part biomass. Regarding to fresh and dry root biomass, control treatment showed the highest value (0.57 and 0.10 g, respectively). Higher doses of GA3 promote plant growth in height and increase in mean length shoot. Doses of 50 mg/L of GA3 are sufficient to promote a significative growth of plant.