Plant regeneration from in vitro leaves of the peach rootstock 'Nemaguard' (Prunus persica x P. davidiana)

A complete protocol for adventitious shoot regeneration was developed from the leaves of peach rootstock 'Nemaguard'(Prunus persica x P. davidiana) grown in vitro. Shoot explants were cultured in vitro in Murashige and Skoog medium supplemented with 3.55 mu M 6-benzyladenine and 7.38 mu M indole-3-butyric acid (IBA). Non-expanded leaves along with their petioles from 3-week-old in vitro-grown shoots were used as explants. Regeneration percentage was influenced by plant growth regulators, basal medium, explant type, dark period, and gelling agents. Optimal regeneration was observed with leaf explants wounded by transverse cuts twice along the midrib and first incubated with abaxial surfaces facing upward in the dark for 3 weeks, and then transferred to the light and cultured with the adaxial side in contact with regeneration medium, as seen on 1/2 MS, woody plant medium or Schenk and Hildebrandt medium supplemented with 9.08 mu M thidiazuron, 0.54 mu M IBA and 0.25% agar. This produced the highest regeneration percentage at 71.7% and a mean of 5.74 +/- A 3.24 shoots on 1/2 MS medium. Adventitious shoots were rooted (98.3-100%) and rooted plantlets survived after acclimatization to the greenhouse.