Abstract
To elucidate the roles of plant growth regulators during fruit development in highbush blueberry (Vaccinium corymbosum L.), we investigated indole-3-acetic acid (IAA) and abscisic acid (ABA) concentrations, ethylene evolution in fruits during fruiting to ripening in ‘Berkeley’, and the ABA concentration and ethylene evolution at color stages of fruits in ‘Earliblue’, ‘Berkeley’, and ‘Jersey’. The IAA concentration increased during seed enlargement. During the maturation stage, the change in the ABA concentration resembled that of ethylene evolution. Ethylene evolution peaked at the same or one color stage earlier than the ABA concentration. The ABA concentration increased simultaneously with ethylene evolution in ‘Earliblue’ and ‘Berkeley’, and the ABA concentration increased later than ethylene evolution in ‘Jersey’. Furthermore, color stages with each of the ABA concentration and respiration rate peak, which is earlier, differed among cultivars. The relationship between ABA and anthocyanin concentrations seems to differ among cultivars. It was found that the ABA concentration changed simultaneously with fruit firmness as well as total soluble solid contents.
