ARS | Publication request: Increasing Phenotypic Diversity in Hydrangea macrophylla Using Targeted and Random Mutation

Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 21, 2008
Publication Date: July 21, 2008
Citation: Greer, S.P., Reed, S.M., Adkins, J., Rinehart, T.A. 2008. Increasing Phenotypic Diversity in Hydrangea macrophylla Using Targeted and Random Mutation. American Society of Horticulture Science Meeting.

Technical Abstract: We have developed an improved in vitro procedure for germinating viable Hydrangea macrophylla seed. Consequently, we have broadened our capability for selecting germlings that in the past may have initially died in nature or, were passed over (in breeding programs) in favor of more hearty, faster growing seedlings. This has proven useful to increase phenotypic diversity in chemical (e.g. EMS) and radiation (e.g. X-ray) mutated seeds since eventual survival of germplasm generated by these methods has been optimized. Likewise, our added capability to make regenerative (leafy) callus has allowed us to pursue “targeted” mutation via RNAi and enhanced gene expression. As a result, we have targeted seeds, young germlings, and callus for transformation by Agrobacterium tumefaciens vector constructs with the aim of modifying hormone levels and enzymes known to produce desirable phenotypic traits. The success of our efforts in H. macrophylla will serve as a valuable tool and model for increasing the diversity of desirable phenotypic traits in the germplasm of other economically important ornamental crops.