Ki Yeol Lee

Effect of biocide addition on plantlet growth and contamination occurrence during the in vitro culture of blueberry

Interest and great demand for blueberry (Vaccinium corymbosum) have increased, as V. corymbosum is now one of the most economically important crops in Korea. It is expected that blueberry production and the area planted for cultivation will increase consistently in the years ahead because of high profitability and the consumers demand for healthy ingredients. Effective mass production of blueberry is urgently needed for commercial cultivation establishment, but a main limitation is lack of a propagation system that produces a disease-free plant material for commercial plantation. A large amount of research has focused entirely on developing tissue culture techniques for blueberry propagation. However, controlling fungal and bacterial contamination of woody plant material is extremely difficult. Our study was conducted to investigate the effect of biocide addition during the in vitro culture of blueberry on plantlet growth and contamination occurrence. Four biocides, including Plant Preservative Mixture (PPM TM ), vancomycin, nystatin and penicillin G, were used in varying concentrations during the in vitro propagation of blueberry. When nystatin was added into the medium at low concentrations, the overall growth of blueberry plantlets was retarded. Addition of vancomycin and penicillin G in high concentrations decreased contamination but induced plantlet mortality. On the other hand, when 1ml/L PPM TM was added, the growth characteristics of blueberry plantlets did not significantly differ from non-treatment (control), and the contamination occurrence rate was very low. From these results, we found that the addition of the appropriate biocide could provide an effective method to reduce contamination in the culture process, thereby raising in vitro production efficiency.

Applicability Using Floral Foam Media in Hydroponic of Rosa hybrida

The study was conducted in a greenhouse to examine the possibility of floral foam media use in hydroponic of Rosa hybrida. pH change in medium of rockwool, coir and floral foam at early time was stabilized from 5.6 to 6.2. However after 2 years, hydroponic culture system became acidic from 4.7 to 5.1. EC was higher in coir media than in rockwool media and floral foam media immediately after nutrient solution irrigation. However rockwool was 2.3 dS·m, coir was 2.5 dS·m and floral foam media was 2.7 dS·m at the hydroponic system after 2 years. Fluctuation of ion accumulation was detected in each media. Only T-N was increased at rockwool media. All components of fertilizer were generally increased in floral foam medium. In coir medium, T-N and CaO was increased while K2O, P2O5 and Na2O were decreased. Rooting rate by different media in Rosa hybrida cutting was effective in orders of floral foam, rockwool and coir. In case of growth, length of cut flower was increased in rockwool media culture. But significant differences were not found in flower height, flower diameter and cut flower harvest yield. Overall, compared with media of rockwool and coir, floral foam was equivalent. Therefore, in hydroponic culture of Rosa hybrida, the obtained results seem that rockwool and coir can be replaced to floral foam.