In vitro Induction of Tetraploid Roots by Various Pretreatments

Abstract: This experiment was done to determine the optimum conditions for the induction of tetraploidy in Panax gin-seng C. A. Meyer using bud length, temperature and plant growth regulator pretreatments. Highest callus formation was obtained when the medium was inoculated with flower bud in the size of 2-3 mm in length. The optimum temperature for the callus formation was high when treated at 4oC for 4-5 days. Among the treatments of growth regulators and dif-ferent concentration, highest callus formation was observed in combination of 5 mg/L 2,4-D and 1 mg/L kinetin for P. ginseng. As a result of flow cytometer analysis, all 7 adventitious roots were confirmed as tetraploidys. Cytological anal-ysis revealed that the chromosome number of tetraploid roots was 96, while that of diploid roots was 48. Tetraploid gin-seng roots were inoculated to flower bud size of 2-3 mm in length. The callus formation was optimum when treated with l mg/L 2,4-D at 4oC for 5 days. Compared with control roots, tetraploid roots were thicker and longer and had few lateral branches. Fresh weight of tetraploid roots was relatively higher than the control roots