Beta maritima. The origin of beets

Abstract

The book is dedicated to Beta maritima, a single species of the genus Beta and progenitor of various cultivated relatives known as sugar beet, garden beet, mangold, fodder beet and energy beets. Importantly, B. maritima is closely related to sugar beet, the only crop for sucrose production under temparate climate conditions and a crop with high potential for sustainable energy. The book is divided into eight chapters with multiple subheadings, each highlighting different aspects of B. maritima. In general, the book is well illustrated with many figures printed in colour. The first chapter describes the history of B. maritima and its domestication. Early uses as a wild vegetable, herb or medical plant were followed by cultivation, which most likely began in Asia Minor, one of the natural habitats of the species. This chapter is very nicely illustrated and interesting as it gives a comprehensive overview of many ancient bibliogaphic sources with references to beet. However, the final part of this chapter describing the life and merits of scientists working on sea and cultivated beet is rather lengthy. The second chapter, entitled ‘Range of Distribution’ is short and focusses on the native distribution of B. maritima along seashores. The species is very tolerant and has a large environmental adaptibility to conditions such as high salinity and poor soil, which is related to its extreme genotypic and phenotypic variation. Beta maritima crosses efficiently with sugar beet and produces viable seeds. Contamination of sugar beet seed lots in combination with trading and shipping is considered to be the main route for the widespread occurrence of B. maritima outside European or Mediterranian coastal areas. The subject of the chapter ‘Morphology, Physiology and Ecology’ is, as its name suggests, rather broad. It gives detailed descriptions of the life cycle of sea beet from germination, organ growth and development, to flowering. This chapter gives an interesting account of pollen morphology and dispersal, and gene flow. Gene flow is generally low between sea beets and crops in areas of sugar beet seed production, but can reduce the allelic diversity of sea beets. Other topics in this chapter include reproduction systems, male sterility, interspecific crosses and survival strategies. The taxonomy is an important issue and subject of the forth chapter, and the authors give a comprehensive overview about the numerous attempts to classify Beta species, which had already started in the late 17th century. The current status of the taxonomy of the genus Beta is still not satisfactory, even after splitting of the Procumbentes section from the genus. Hence this chapter is a valuable contribution, although a conclusive taxonomy of the genus is missing and still a matter of future research, as the authors correctly state. After a short consideration of the historical and potential use of sea beets in Chapter 5, Chapter 6 is a major and important part of the book. Beta maritima is extremely important for sugar beet breeding and serves as the main reservoir and source for resistance genes. The species is resistant against many pathogenes, in particular viruses and fungi, but also to nematodes and insects. Moreover, B. maritima is highly tolerant to drought, heat and, as mentioned above, salanity. Most importantly, sea beets can easily be crossed with sugar beet, thus providing a route for the transfer of genes for desirable agronomic traits into cultivated beet. The domestication of the sea beet as a vegetable initiated the selection of highly variable cultivars with enlarged root hypocotyles, which are nicely described and illustrated in Chapter 7. This chapter is entitled ‘Cultivated Offspring’ and covers chards, garden beet, sugar beet, fodder beets and energy beets. The latter are used for the fermentation of bioethanol, and controversial aspects of increasing either yield or sugar content are dicussed. Less importantly, but for completeness, this chapter also contains a short paragraph about ornamental beet. However, the main focus is on sugar beet and breeding aims as major crop of the genus Beta. Beta maritima introgressions are the main ressource to broaden the narrow gene pool of sugar beet. This topic is addressed in Chapter 8, where the importance of germplam conservation, collection and genebank management is described. The species of the genus Beta, in particular sugar beet, have been targets of genome analysis projects, such as marker development for genetic linkage maps, resistance gene cloning, genome sequencing and evoluionary studies of repetitive DNA sequences. It is a shortcoming of this book that most of these papers (published in international peer-reviewed journals) are not mentioned or cited. Beta maritima: the origin of beets is, in my opinion, not a textbook for students or undergraduates but it is a valuable resource for scientists involved in Beta germplasm conservation and taxonomy, as well as breeders interested in sea beet and beet history in general.