FOREWORD

Although the aim of this workshop is similar to the above series its subject matter is different. This workshop reviewed relevant research over the last few years in the genetics and physiology of dwarfing fruit trees. Substantial advances are reported. Genetic dwarf trees have been developed in almost every fruit species. There are several ways the compactness of the tree is brought about. Although the underlying physiology is not clear at present the horticultural usefulness of these new dwarf types may be quite high in the future. The physiology of various horticultural practices such as early cropping, pruning, regulating the water availability to the trees and their regulating effect on tree size was also reviewed. The dwarfing of trees by growth regulators has been the concern of a substantial number of research workers for several years. This subject was also discussed during the workshop and the conclusion emerged that growth regulators, in all likelihood, will play a more important role in the development of future high density orchards.

This workshop can be regarded as a milestone. In the past we limited our research on vigor control. Today we regard vigor as only one of several components that contribute to the compactness of the tree. There are ways to dwarf a tree other than control vigor, which were exposed and discussed for the first time during this workshop. Thus, I consider this workshop as an important broadening of our viewpoint with respect to dwarfing. After listening to the entire scope of the contributions, it was clear that the title of the workshop could well have been something like "Components of Compact Character in Fruit Trees." The present title is somewhat limiting in view of the broad subject of the workshop as it turned out to be. I apologize to all the future readers who were mislead by the title as a result of my not foreseeing this.

Miklos Faust
Convener


ACKNOWLEDGEMENTS

It is a pleasure to acknowledge the help of all participants of the workshop whose presentations and/or contribution to discussions ensured the success of the workshop.

Thanks are also due to the American Society for Horticultural Science for sponsoring the workshop, and especially to Cecil Blackwell, Executive Director, for his assistance.

We thank Dr. H. M. Cathey, Director of the National Arboretum, and Dr. George Green of Pennsylvania State University, Biglerville, PA, for the excellent tours of the Arboretum and the Adams County Pennsylvania fruit growing area.

Much help and financial support were provided by the Beltsville Agricultural Research Center and we especially thank Dr. Paul A. Putnam, Director of the Center, for his assistance.

Special thanks are due to the secretarial and technical staff who were responsible for the many tasks necessary for the successful and efficient organization of the symposium.

Miklos Faust, R. F. Korcak, S. Zagaja