Selection of Optimum Culture and Subculturing Conditions for Multiple Shoot Induction and Proliferation of Phalaenopsis

This study was aimed at investigating the effects of different culture media, plant growth regulators, and subculturing conditions on multiple shoots formation from Phalaenopsis flower stalks. The optimum medium for multiple shoot induction was half-strength (1/2) MS medium, which was more efficient than VW or Hyponex medium. Proper concentrations of BA and TDZ for both multiple shoot induction and propagation were 5.0 ㎎ㆍL?¹ and 1.0 ㎎ㆍL?¹, respectively. As the number of subcultures increased, the ratio of malformed shoot productions increased with a low frequency up to the third subculture. When subcultured six times or more in Dtps. ‘Minho Princess’, P. ‘New Cinderella' and Dtps. 'Taisuco Firebird', the percentage of shoot malformation was close to 30%. The maximum length of subculture period was observed to avoid malformation of shoot. When subcultured for the first time for two months after planting on medium, all cultivars produced few malformed shoots, and subsequently as the length of subculture period increased, the frequency of shoot malformation increased. Therefore, subculturing at least every two months was desirable.