Adventitious shoot regeneration from leaf explants of southern highbush blueberry cultivars

Protocols were developed to optimize adventitious shoot regeneration from four southern highbush blueberry cultivars. Leaf explants from 6 week-old shoots of the four cultivars were excised and cultured on woody plant medium each containing thidiazuron (4.54 or 9.08 mu M), zeatin (18.2 mu M), or zeatin riboside (5.7 or 11.4 mu M) either separately or in combination with alpha-naphthaleneacetic acid at 2.69 mu M. Optimum medium for shoot regeneration was genotype-dependent. Efficient regeneration was obtained at frequencies of 88.9% for 'Jewel', 87.8% for 'Emerald', 53.3% for 'Jubilee' and 87.8% for 'Biloxi'. Leaf explants of newly developed shoots from the cultures having undergone five subcultures had higher regeneration frequencies than those having undergone two subcultures. Regenerated shoots, 80-100% for each cultivar, rooted in 8 weeks after transplantation to soil. The regeneration systems described have potential use in genetic transformation of southern highbush blueberry cultivars.