Studies On Shoot Regeneration From Leaf Section Of Blueberry And Affecting Factors Of Shoot Regeneration

A procedure to regenerate shoots in vitro from leaf sections of fourteen blueberries genotypes, 'Gardenblue', 'Sunrise', 'Sierra', 'Duke', 'Berkeley', 'Elliot', 'Bluecrop', 'Jersey', 'Georgia Gem', 'Reveil', 'Sharpblue', 'Northland', 'Blomidon', 'Fundy', in Woody Plant Medium was established, and influencing factors such as genotype, medium, hormone, sugar concentration, pH, were also studies.Cultivars with different genotype had different regeneration ability. Among the fourteen genotypes tested , 'Sunrise', 'Sierra', 'Georgia Gem' and 'Fundy' had the strongest ability in shoot regeneration with shoot induction frequency of 95% and mean number 20 shoots per leaf. Hormone types and concentration in medium were the most important factors influencing shoot regeneration from leaf segments of blueberry. The effect of Zeatin and CPPU on leaf segments regeneration was better than other hormones tested in experiment. Cytoinin TDZ or 2ip had effect on some cultivars. For example, regeneration percent of Sunrise obtained from 2ip medium was 59.4% or 69%, which was fewer than that from Zeatin or CPPU medium. Medium supplemented with the cytokinin CPPU was compared with medium supplemented with Zeatin. Use of 1.0 mg/L ~ 2.0 mg/L CPPU resulted in the higher regeneration rate and larger number of shoots per leaf section than 5.0 mg/L Zeatin did. Such as Georgia Gem , its highest regeneration percent on CPPU medium was 100%, while on the Zeatin medium was 42.3%. Consequently, we concluded that the cytokinin CPPU was more effective than either of the cytokinins, Zeatin, 2ip or TDZ, in promoting shoot regeneration from leaf sections of blueberry. Dark treatment was also important factor in blueberry leaf section regeneration. Ten days dark treatment after leaf sections inoculated on the medium promised the best adventitious buds and highest regeneration rate. And shorter or longer than ten days would decrees shoot regeneration rate. In addition, sugar concentration and pH had effect on blueberry leaf sections regeneration. Medium with 20mg/L sugar was optimum of leaf regeneration , producedmore shoots than any other concentrations of sugar. The optimal pH of medium was 5.4. The shoot regeneration rate of blueberry would be decreasing with pH of medium increasing. For example, the shoot regeneration rate of Georgia Gem on pH 5.4 medium was 97%, while on pH 6.5 medium the shoot regeneration was 10%. The temperature during dark treatment influenced shoot regeneration too. The optimal temperature of low bush blueberry was 20 ± 2 ℃ , for high bush blueberry was 25 ±2 ℃. The optimal temperature of rabbiteye was higher than 25 ± 2 ℃., but lower than 30℃.