Plantlet regeneration of adult <Emphasis Type="Italic">Pinus massoniana</Emphasis> Lamb. trees using explants collected in March and thidiazuron in culture medium

A protocol for micropropagation using nodal explants from mature Pinus massoniana trees has been developed. Time of explant collection is crucial for the initial success of aseptic culture. Explants collected in early March gave the highest percentage of explant survival (64.5%) and shoot-forming percentage (52.3%). Thidiazuron (TDZ) concentration significantly influenced shoot formation; 4 μM TDZ was optimum, with 4.8 shoots produced per explant with a mean length of 7.1 cm after 120 days of culture. Regenerated shoots rooted for 60 days in basic medium with 1 μM NAA were ready for growth in pots. This is the first report on plantlet regeneration in vitro from mature trees of P. massoniana that provides a reliable method for propagating selected elites.