FOREWORD

The organization and hosting of a truly international symposium requires the dedicated involvement of many people and as the General Chairman of the Growth Regulators Working Group (Professor S. Sansavini resigned this position to become Chairman of the Fruit Section of ISHS in 1986) and the Symposium Organizer, I would like to acknowledge the helpful participation of the International Organizing Committee and the members of my Local Scientific Committee. Especially important and helpful discussions were held with Professor Sansavini, Dr. J.D. Quinlan, Dr. F. Jaumien, Dr. E.A. Curry and Professor L.E. Powell. Much closer to home, I received yeoman service from my colleagues and co-workers Dr. A.G. Reynolds, Miss C. Zurowski, Mrs. L. Kerr and Mrs. J. Rogall. Excellent editorial assistance was provided by Ms. P. Watson.

It is also appropriate to acknowledge the cooperation and involvement of the Summerland Research Station administration and staff in the hosting of this event. A tour of this modern Agriculture Canada facility was a highlight of the meeting for many participants. Special thanks to the Director, Dr. D.M. Bowden, for his cooperation in authorizing the many months of involvement in this project by the Symposium Organizer.

Of particular significance to the readers of this volume is the fact that all contributed papers were reviewed by at least three members of an international Editorial Board headed by Dr. L.C. Luckwill. The Editorial Board decided upon the appropriateness and acceptability of each contribution and helped the Symposium Organizer identify those papers to be featured as oral presentations. All papers included in this Acta were presented at Penticton either as a poster, a contributed paper selected for oral presentation, or as an invited lecture. The high quality of the symposium presentations and of the papers in this Acta is due, at least in part, to the dedicated service of the Editorial Board.

As Editor-in-Chief, Dr. Luckwill accepted the responsibility for the final editing and assembly of the Acta. He also performed the detailed editing of all contributed papers and arranged for the necessary retyping. The editing of the invited papers was done by Drs. Powell and Looney.

In his Foreword to the previous Symposium (Rimini, Italy, 1985), Dr. L.E. Powell referred to the growing public concern about agricultural chemicals in general and plant growth regulating chemicals in particular. His observation that it will become increasingly difficult to register new plant growth regulating chemicals for use in fruit production continues to be an accurate statement. For example, the registration of paclobutrazol for the control of vegetative growth on a number of important fruit tree species, considered a virtual certainty in 1985, is now a matter for debate in North America and parts of Europe. On the other hand, despite a vigorous and continuing public debate, daminozide retains its registered uses in most fruit growing countries. Its history of effective usage, evidence affirming its toxicological safety, and its economic importance to apple producers world-wide have led most registration authorities to continue to support this versatile PGR.

Thus, while in many countries there continues to be a vocal segment of the public that questions all aspects of technical agriculture, and is especially critical of the use of agricultural chemicals, we can expect that PGRs will continue to be important in fruit production for some time to come. However, the number of materials available to the fruit industry will increase very slowly, if at all, and I suspect that they will focus increasingly on the enhancement rather than the inhibition of endogenous growth substances. We will be challenged to find ever more innovative uses for ethephon, the gibberellins, natural and synthetic auxins and cytokinins, chemicals with abscisic acid-like activity, and perhaps the polyamines. We will also be called upon increasingly to explain and defend our activities in this very interesting and important sub-discipline of horticultural science.

It is quite clear that the initial industry screening of new chemicals for PGR activity will continue to emphasize agronomic rather than horticultural crops. Thus, those of us concerned with pomology will find it necessary to initiate the testing of potentially important chemicals on fruit crop species; a task requiring a full appreciation of the many and varied opportunities for regulation.

Some of the topics emphasized at this Sixth Symposium were selected because they may bring to light such opportunities. For example, it may be possible to improve tree and vine productivity by directly influencing the efficiency of the "source", the strength of the "sink", or the speed of movement of carbohydrates from source to sink with plant growth regulating chemicals. Similarly, PGRs may have a role to play in the prevention or amelioration of stress in fruit trees. We can search for such activity if we have an adequate understanding of the physiological processes involved.

Thus, the fundamental bond among scientists attending this, and past symposia in this series is the common desire to better understand the regulation of growth and development in perennial fruit trees and vines. There is still much to be learned.

The next symposium is planned for 1992 and will be hosted by Israeli scientists at The Volcani Center and the Hebrew University Department of Horticulture. The Local Organizing Committee will be headed by Dr. Raphael Goren.


Dr. N.E. Looney
General Chairman of the Working Group
Head, Pomology and Viticulture Section
Agriculture Canada, Research Station
Summerland, B.C. VOH IZO CANADA


ACKNOWLEDGEMENTS

The organizers of this symposium acknowledge with thanks the generous financial support of the following corporate and non-corporate sponsors:-

Abbott Laboratories: Chemical and Agricultural Products Division, North Chicago, IL, 66064, U.S.A.

BASF Aktiengesellschaft, Crop Protection Division, D-6703 Limburgerhof, FGR

British Columbia Ministry of Agriculture and Fisheries, Victoria, B.c. V8V 1X4, Canada

Chevron Chemical Company, Agricultural Chemicals Division One Crossroads of Commerce, Rolling Meadows, IL, 60008, U.S.A.

Controlled Environments Ltd, 1461 St James St., Winnipeg, MB, R3H, 0W9, Canada

The Dekaban Foundation, Vancouver, B.C., Canada

ICI Agrochemicals, Bracknell, Berkshire, RG12 6EY, U.K.

Rhone Poulenc Agrochemie, B.P. 9163, 69263 Lyon Cedex, France

Uniroyal Chemical Company, 74 Amity Road, Bethany, CT, 06525, U.S.A.


OPENING ADDRESS

Honourable Minister and Mayor, Mr. Chairman, ladies and gentlemen and dear friends:

It is with great pleasure that I extend today the welcome of the ISHS and its Fruit Section to you here at the Sixth International Symposium on Growth Regulators in Fruit Production amid the beauty and gracious hospitality of Penticton.

Let me here remark that our Society has today more than 2500 members worldwide. The calendar of events is very full with 10 or more international symposia scheduled by the ISHS in an average year. Scientists who wish to join the Society are welcome.

Of the 15 Working Groups of the Fruit Section, the Growth Regulator Group is undeniably the longest standing and one of the most active. It was established over 20 years ago thanks to the initiative of several distinguished researchers who are present with us today. Let me single out Dr. Leonard Luckwill (U.K.) and Dr. Max Williams (U.S.A.) as representing the founding members and extend to them our sincere thanks.

Throughout this span of time, many scientists from many countries have been actively engaged in promoting the group's work. So many, in fact, that we numbered over 500 at one point when this list included non-ISHS members identified as being involved in growth regulator research with fruit crops.

While we are not so numerous at present, this does not mean that we are less qualified. For it is to be noted that in these last 20 years the scope and direction of growth regulator research have changed considerably. Initially, the emphasis was on understanding these chemicals and their effectiveness. This phase then gave way to studies on plant responses, modes of action, uptake and transport mechanisms, and metabolism and degradation. Some of us are currently studying biosynthesis and molecular targets, enzyme interaction, genetic codes and gene expression.

Some of our colleagues, whether those of little faith or those pursuing other seemingly more attractive lines of research, feel that the investigation of growth regulators is not as topical as it was just a few years ago. This is, of course, far from the truth, as the papers to be presented at this Symposium so eloquently demonstrate. For it is through these very studies that we shall gain important insights into growth physiology, flower induction, sink competition and other plant processes. Even the study of endogenous growth substances alone, if coordinated with biochemists and molecular biologists, can enhance our knowledge more than plant physiologists can do alone. Let it not be forgotten that most of us are pomologists engaged in applied plant physiology. Indeed, our research together with that focussing on the environment and on biotechnology contributes directly to improving the on-the-job safety, health and crop management techniques of fruit growers.

Let me conclude my remarks by warmly thanking our host, Dr. Norman Looney, and all the members of his staff for their outstanding organization; Dr. Leonard Luckwill, to whom a particular thanks is also due for his efforts in past symposia, and the other members of the Editorial Board; the members of the Scientific Committee; and the generous sponsors listed in the program. Let me just add my thanks to all of the participants and wish everyone a successful symposium!

Professor silviero Sansavini
ISHS-Fruit Section Chairman
Istituto Coltivazioni Arboree
University of Bologna
Via Filipino Re 6
40126 Bologna, ITALY