A protocol for the production of transgenic Panax ginseng C.A. Meyer was established via Agrobacterium tumefaciens-mediated genetic transformation of direct somatic embryos. A number of conditions related to the co-cultivation were tested with respect to maximizing transformation efficiency. The results showed that pH of the co-cultivation medium (5.7), the bacterial growth phase (optical density; OD600 = 0.8), co-cultivation period (3 days), and acetosyringone concentration (100 μM) had positive effects on transformation. Selected plantlets were cultured on the medium at an elevated hygromycin level(30 mg/l). Integration of the transgenes into the P. ginseng nuclear genome was confirmed by PCR analysis using hpt primers and by Southern hybridization using hpt-specific probe. The transgenic plantlets were obtained after 3-month cultivation and did not show any detectable variation in morphology or growth characteristics compared to wild-type plants.

The cost of conventional cultivation of ginseng (Panax ginseng C.A. Meyer) is very expensive, because shadow condition should be maintained during cultivation periods owing to inherently weak plant for high-temperature. Therefore, application of plant biotechnology may be possible to overcome these difficulties caused by conventional breeding of ginseng. Transgenic plants were produced via Agrobacterium tumefaciens Gv3101, both carrying the binary plasmid pBI121 mLPISO with nptII and Iso (isoprene synthase) gene. Integration of the transgenes into the P. ginseng nuclear genome was confirmed by PCR analysis using nptII primers and Iso primers. RT-PCR result also demonstrated the foreign isoprene synthase gene in three transgenic plant lines (T1, T3, and T5) which was expressed at the transcriptional level. When whole plants of transgenic ginseng were exposed to high temperature at 46℃ for 1 h, a non-transformed plant was wilted from heat shock, whereas a transgenic plant appeared to remain healthy. We suggest that the introduction of exogenous isoprene synthase is considered as alternative methods far generating thermotolerance ginseng.

This experiments were conducted to evaluate suitable plant-type and cultivars for producing fresh pod peanut from late seeding as succeeding crop, compared with early seeding as proceeding crop or single cropping. 12 cultivars according to grain weight and plant types, 6 virginia typed cultivars(ssp. hypogaea) and 6 shinpung typed cultivars(ssp. fastigiata), were used for early and late seedings. The plant growth and yield potential in early seeding were better than those in late seeding. But the ratios of dry/fresh pod and of mature pod in late seeding were higher than those of early seeding. The yield of fresh pod by cultivars in two seeding times showed significant correlation with pod scale such as fresh pod weight, 100-grain weight, and dry seed yield positively, but pod number negatively in early seeding only. Yield of fresh peanut between Virginia and Shinpung types didn't show significant difference in early seeding, but showed in late seeding. Average yield of Virginia typed cultivars showed significantly higher than that of Shinpung typed ones. This yield gap between two plant types was the same tendency on extending seedings to July 20.