사과 대목 M.26 (Malus pumila Mill)의 기내 대량번식 및 simple sequence repeat 마커를 이용한 증식된 식물체의 유전적 다양성 평가

In vitro micropropagation of M.26 (Malus pumila Mill) apple rootstock and assessment of the genetic diversity of proliferated plantlets using simple sequence repeat markers

The objective of this study was to determine the most effective medium condition of shoot proliferation and root formation for the efficient in vitro micropropagation of M.26 (Malus pumila Mill). Simple sequence repeat (SSR) markers were used to analyze the genetic diversity of micro-propagated and greenhouse grown M.26. Shoot proliferation was carried out in MS (Murashige and Skoog) containing benzyladenin (BA, 0.5 ~ 5.0 mgㆍL-1) and thidiazuron (TDZ, 0.01 ~ 0.1 mgㆍL-1). The highest number of shoots (10.67 shoots per explant) was induced by adding BA at a concentration 1.0 mgㆍL-1. TDZ treatments caused higher hyperhydricity rate in cultured explants than in BA treatments. There was no significant effect of both BA and auxin on shoot proliferation, and the optimum proliferation medium for M.26 was MS medium containing 1.0 mgㆍL-1 BA. To find a suitable medium composition for shoot rooting, we tested different concentrations indole-3-butyric acid (IBA) and α-naphthaleneacetic acid (0.5 ~ 5.0 mgㆍL-1), MS medium (1/4-1), sucrose (0 ~ 30 gㆍL-1). The shoots showed good rooting on half-strength MS medium containing 1.0 mgㆍL-1 IBA and 15-20 gㆍL-1 sucrose. The rooting rate (100%), number of roots (10.45 ~ 13.60 roots per explant), root length (7.41 ~ 8.33 cm), and shoot length (4.93 ~ 5.38 cm) were good on this medium. Fifteen SSR primers were detected in a total of 30 alleles in 20 micro-propagated plantlets, all SSR profiles from micro-propagated plantlets were monomorphic and similar to greenhouse grown control plantlet M.26 plant. The results indicated that M.26 micro-propagated plantlets were genetically stable.