Response of highbush blueberry seed germination to gibberellin A3 and 6N-benzyladenine

Abstract

Open-pollinated highbush blueberry (Vaccinium corymbosum L.) seeds were treated with 0, 2.6, 5.2, 10.4, or 20.8 mM gibberellic acid, 0, 0.4, 2.2, or 4.4 mM 6N-benzyladenine, or the two growth regulators in combination. Seeds were treated for 24 h, then germinated under intermittent mist during summer with temperatures fluctuating between 21 and 40 °C. Germinated seeds were counted weekly from day 15 to day 30, using hypocotyl exposure to indicate germination. Treatment with gibberellic acid at 10.4 mM in combination with 6N-benzyladenine at 0.4 to 2.2 mM gave the highest germination percentage. The relationship between gibberellic acid concentration and seed germination was cubic. Seedlings from the germinated seed flowered and fruited the following spring, making it possible for highbush blueberry to complete a generation in 1 year.