Abstract
Shrub willows are fast growing woody species that have many ecological and economic applications. This study examined the effects of explant and hormone types on in vitro plant regeneration and Agrobacterium-mediated transformation using bioenergy-producing and a locally threatened willow species, Salix cordata. The goal of this study was to regenerate willow from calli for mass propagation and/or genetic transformation. Optimized protocol for calli induction was achieved in bioenergy-producing willow, which will facilitate shoot regeneration for future studies. Salix cordata explants produced 89 plantlets, representing 12% of all treated calli. The calli subjected to Agrobacterium produced 9 plantlets that survived antibiotic selection. Whole plant regeneration starting from culture of explants took 15 weeks. The S. cordata regeneration protocol developed in this study can be used to produce many plantlets to increase native population size or for experiments to better understand the impact of the current threats to the population.