Adventitious regeneration of Juglans nigra L. (eastern black walnut)

Somatic embryos and adventitious shoots were initiated from immature cotyledons 10-14 weeks after anthesis. Maximum embryogenesis occurred 12 weeks after anthesis and maximum shoot organogenesis occurred 14 weeks after anthesis. The best treatment for induction of somatic embryos and adventitious shoots from immature cotyledon explants was on agar-solidified WPM supplemented with 0.1 μM 2,4-D and 5.0 μM TDZ and incubated in light for the first four weeks. Rooting of adventitious shoots was best if they were quickdipped in 2.5 mM IBA and 1.25 mM NAA in 1% dimethyl formamide and 3.9% ethanol (1∶20 Wood's Rooting Compound: water, by volume). Plantlets from rooted adventitious shoots were acclimatized to the greenhouse.