The physiology of crop yield, 2nd edn

The title and the introduction announce clearly that the book is about the physiological processes determining the yield. Crop physiology is said to be distinct in that it provides useful information about plants growing singly and in stands under controlled conditions or in the field. There was a time when providing students with appropriate material for a crop physiology course of good level required an important work of selection and integration of information scattered through many different types of journals and textbooks. Now the situation has changed and there is a range of textbooks available focussing on crop physiology. The books differ in the ratio between fundamental and more practical aspects of crop functioning that are presented. In this book the authors choose to keep as a central core the analysis of yield in terms of interception of radiation, its conversion into chemical potential energy and the partitioning of the resulting dry matter. Resources other than carbon, principally water and nitrogen are also considered. The approach is quantitative, integrative and takes account of interactions. This is particularly illustrated by an extensive chapter on modelling and references to models in other parts of the book. Aspects of crop quality are not forgotten, with a whole chapter being devoted to it. There are also more fundamental reminders about science that are interesting: ‘to be a scientist requires having a model in mind’; causality is multifaceted. Thus the book extensively covers the theoretical aspects of crop physiological processes that have profound effects on the potential and real production of major agricultural crops. It includes chapters on development and phenology (a new chapter not found in a previous edition), interception of solar radiation by the canopy, photosynthesis and photorespiration, respiration, partitioning of dry matter, limiting factors and the achievement of high yield, physiology of crop quality, modelling of crop growth (expanded in comparison to the previous edition) and prospects for the future of crop physiology. The book remains markedly production orientated. It provides a synopsis of the quality- and yield-determining processes. It is useful for understanding and interpreting agronomic phenomena and therefore clearly has a considerable value to advanced students, teachers and scientists in the field of agronomy, crop management and even plant breeding. It should also benefit scientists and students who study plant physiological processes at the sub-plant and sub-organ levels, and who look for a context for their work at the level of whole stands of plants whether it is related or not to agricultural crops. The book may be less accessible and therefore less attractive to professionals working in agriculture. One of the reasons is the rigorous approach that integrates several disciplines such as biochemistry, plant physiology etc., from the biochemical to the whole-plant crop level. A basic knowledge of these disciplines seems to be a prerequisite for being able to fully benefit from this book. Another reason may be the abandonment of case histories, although clear references to selected crops are given in examples throughout the text. Presentation on a separate per crop basis may seem at first sight closer to field practice than presentation on a per plant-process basis. The examples are also limited to a few field-crop species (wheat, soybean, maize, potato) and to grassland. Finally, although mention is made (in chapter 9) that combined genetic, environmental and management factors drive plant processes, otherwise little reference is made to management factors throughout the text. These limitations are explained by the broad range of topics related to crop issues and the necessity to limit the scope of the book. The presentations of the different topics are done in depth, they are up to date, clear and generally backed by appropriate selected references from the literature. The array of literature cited is broad and also up-to-date: the authors have not merely transfered information already available in other textbooks. Of course, they had to make choices – the literature being huge and often redundant – and these choices have naturally been influenced by the professional environment and the origin of the authors. The integrated body of information given would have taken an enormous amount of time for an individual to collect and summarize if working alone. The order of presentation is logical and comprehensive overviews are given. Short summaries imbedded in the text are quite useful. Topics such as sustainable production, perspectives from the gene to the plant and frpm crop to the ecosystem, advances in molecular biology relating to crop science, and new issues such as effects of global climate change on crop behaviour are mentioned in the introduction but do not receive a full development in the rest of the text, except through a few mentions. We have to wait until chapter 10, about the future of crop physiology, in order to again find considerations about the implications of molecular biology, molecular genetics, etc., and climatic change for crop physiology and vice versa. There is no mention at all of 3D modelling or on degenerated or metamodels used at scales larger than the plot (for instance in remote sensing). Again the authors had to make choices since the field covered by crop issues is very broad, involving different scales of space and time and different disciplines. In the concluding words it is stated that if crop physiology has a role, it has to be in the middle ground between the extreme reductionism of genetic engineering and the wholesale integration of efforts to predict yields and to breed better plants. To achieve that, molecular geneticists and crop physiologists must learn each other's language and funding agencies must support joint interdisciplinary research activities. But a reminder is given that many factors play a role in the damping and averaging out of responses on moving from the genome to the whole plant. This book may have its limitations, but it remains an excellent reference that should be recommended for any teaching of crop physiology at the graduate level. I am also sure reading it would be beneficial even for confirmed crop physiologists.