Rapid In Vitro Propagation of Aruncus `Misty Lace', a New Heat-tolerant, Dwarf, Hybrid Goatsbeard

Abstract

Tissue culture is a useful means to clonally propagate new ornamental plant selections, particularly when plant material is limited and/or conventional propagation methods are ineffective. An efficient in vitro multiplication protocol was established to propagate a new goatsbeard hybrid (Aruncus dioicus, × A. aethusifolia). The hybrid is of interest because it exhibits a dwarf habit, delicate white flower panicles and fern-like leaves, yet is tolerant to heat and humidity. Experiments were conducted to evaluate explant type (nodes, stems, leaves, and floral parts), disinfestation procedures, and media formulations including varying concentrations of 6-benzylaminopurine (BAP) and naphthalene acetic acid (NAA). Rapid plant regeneration was obtained with a shoot organogenesis system using a half strength Murashige and Skoog medium supplemented with 4.4 μmol BAP, 0.54 μmol NAA, 30 g·L-1 sucrose, and 3.0 g·L-1 GelGro. Studies compared the performance and yield of plants rooted using different in vitro and ex vitro methods. Ex vitro rooting of shoots during greenhouse acclimatization under mist was most effective. Regenerated plants exhibited uniform and rapid growth, and performed well in greenhouse and field evaluations.