The Seventh triennial Symposium of the International Organization of Plant Biosystematists (IOPB) took place in Amsterdam, The Netherlands, August 10 to 15, 1998. This volume contains 19 papers based on invited lectures from the symposium. As in previous IOPB symposia, the topic is related to the botanical interests of the host country. ……..

The Netherlands contains interesting and beautiful sites with rare and specialized plants. Their origin and maintenance are the result of human activity just as the large tracts of agricultural land and the land claimed for human occupation. With this symposium we wanted to highlight the evolutionary reactions of plants to anthropogenic influence as a genuine and important subject for biosystematic research. The practical relevance of this aspect of plant evolution is obvious. In addition, plant evolution in response to human activity provides some of the simplest and clearest models for basic questions in evolutionary biology. Human influence tends to speed up evolutionary processes and to produce evident changes that can often be directly related to a specific selective regime. Such fast and dramatic responses are easier to study than events in which more and different selective factors interact over longer periods of time. The first section of the book deals with Evolution in Disturbed Habitats. Among the most pronounced effects are those of heavy metal pollution (W.H.O. Ernst). Other contributions reach from disturbances that bring together previously separated species and initiate introgression and hybrid speciation (K.M. Urbanska and E. Landolt) to agricultural practice preparing the way for camp followers (B. Neuffer). Genetic changes enabling plants to exploit disturbed areas can concern a few key features, and the combination of quantitative genetics with molecular marker maps provides insight in the numbers and effects of the allelic differences between a weed and its wild ancestral species (D.M.L. Purps and J.W. Kadereit). As in many areas of plant biology, the favorable features of the model species Arabidopsis thaliana are being exploited to study an adaptible plant in its newly invaded environment, strongly influenced by man (S. Kawano).

Many of us may instinctively perceive an essential and qualitative difference between "natural" evolution and the reaction of plants to the stresses or opportunities that result from human disturbance. Such a basic distinction is made even more often between "natural" evolution and the results of plant breeding. Still, the genetic processes underlying heritable change are the same in all cases. A section of the symposium dealt with "domestication: simulating evolution". In fact, I believe that domestication is evolution with mankind playing the role of pollinator, disperser, defender and user of plants. Very detailed and well-supported new results on some of the classical cases of crop evolution have recently been obtained with the help of molecular markers. Examples of the remarkable insights recently gained are brought together in section 2 of this volume, "Crop evolution", where studies in maize (J.D. Hill and J. Doebley), cotton, (J.F. Wendel et al.) and Phaseolus beans (P. Gepts) are presented. There also, two papers illustrate that molecular markers shared among related species can be employed for a comparative analysis of the genome structure in Brassicaceae (R. Schmidt et al.) and Triticeae (A. Börner).

The close relationship between "natural" and "managed" evolution becomes evident, where crops come into contact with wild relatives so that gene flow can take place. Section 3 deals with "Crop - wild-relative genetic interactions". In this area, there is the closest cooperation between standard biosystematics and plant breeding. Various aspects of this interaction are hybrid speciation among the relatives of crop plants (L. van Raamsdonk), the assessment of the risks related to transgenic crops (S.I. Warwick and E. Small), interactions between various cultivated beets and the wild Beta maritima (H. van Dijk and B. Desplanque), and introgression in Medicago (P. Rufener and K. Ammann) and Brassicaceae (H. Darmency).

One of the most successful adaptations that allows plants to invade newly opened niches quickly is the combination of polyploidy and apomixis (Section 4, Apomixis). Here, too, molecular methods have provided new insights and finally promise a real breakthrough in the genetic analysis of apomixis (M.D.Hayward). Apomictic plants have traditionally been a touchstone for species definitions and the discussion of the problem raises basic questions on the structure of biodiversity (T.A. Dickinson). In spite of basic similarities, each apomictic complex has some very distinct features, and here as everywhere in evolutionary biology thorough analyses of a variety of examples are the basis for generalizations (C.S. Campbell; R.J. Bayer).

I believe/am sure that the symposium and this proceedings volume will contribute to the understanding of plant biodiversity and its future, also under strongly man-driven environmental circumstances. especially the ever-increasing part of it that is a direct result of human manegement of the plants and their environment.

Konrad Bachmann, President of IOPB
Institut für Pflanzengenetik und Kulturpflanzenforschung, IPK, Gatersleben &
Institute for Systematics & Ecology, Hugo de Vries Laboratory, University of Amsterdam