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Contents:

1 - The case of the bolting beets I; 2 - Hybridization and gene flow, an introduction; 3 - Natural hybridization between plant species; 4 - Evolutionary consequences of gene flow and applied implications; 5 - Evidence for recognizing natural hybrids; 6 - The case of the bolting beets II; 7 - Do important crops mate with wild relatives?; 8 - Is natural hybridization with wild relatives the rule for domesticated plants?; 9- Some impacts of gene flow of domesticated alleles into wild populations; 10 - The case of the bolting beets III; 11 - The 'special' case of genetically engineered plants?; 12 - Whether and how to manage domesticated gene flow into wild populations.

Review:

There is an increasing debate about the use of 'genetically-modified' or 'transgenic' crops often brought to the attention of the general public with headlines noting 'frankenfood'. Although such issues can bring a range of issues into the classroom it's also true to say that 'popular' ideas can cloud the debate. The aim of this text is to subject much of the hyperbole to scrutiny.

If we think about it, speciation is just another example of genetic modification. So how and why do we have this debate about domestic crops (and it is plant rather than animal material that's at the centre of this book)? Perhaps in part its the headlines that have been created. Perhaps in part it's a real concern about the way in which we seek to modify the environment without always taking the ecological consequences into account. It's very much this latter approach that the author seeks to take. The first four chapters, grouped under the heading foreplay aim to examine the science behind this debate. We start with one plant, the beet, that recurs throughout the text. It's main claim to fame is that it hybridizes and also spreads rapidly. It makes a good target to start with as we are shown the consequences of natural flow of genetic material (i.e. pollen) from coastal plants (the beet is a coastal plant) to inland crops. This brief study shows that there can be considerable impact. This moves us on to chapter two which looks briefly at the key concepts and notions of hybridization. Chapter three describes natural cases whilst chapter four explores gene flow and its implications in greater detail. From this point we move into the second part - caught in the act - which comprises 5 chapters each examining a part of the case for natural hybridization. The first chapter here considers the evidence for natural hybrids to occur. It's mainly a basic overview of the various tests that can be carried out to determine genetic origins. Chapter six moves on to look at the next part of the beet saga and the extent to which natural hybrids occur. Leaving the beets for a later chapter, chapter seven evaluates the evidence for key crops to cross with wild stock. In this chapter, the longest in the text, 25 key crops are analysed with the result that the majority will hybridize. The next question is to consider if this occurs with other species and not just key domestic ones. Again, the main evidence points to 'yes' although it is not a universal acclamation. More importantly, we can see that whatever the result, it's not clear cut - there are exceptions to the rule and the complete picture has not yet been revealed. This takes us into the third part, dangerous liaisons? Chapter 9 looks at the impact of the gene flow identified in the first two parts of the text. As with any other aspect the issue is far from either simple or clear cut. The next stage is to return to the beets to see if gene flow can go the other way from domestic to wild. If this happens then it could trigger changes in the wild population which would have wide-ranging consequences. Although it might occur it's also the case that beet production especially in Europe is in decline and that this might skew results. This means one promising line of enquiry is reduced. Chapter 11 takes on one of the more contentious issues - the ability of genetically-modified plants to alter wild stock detrimentally. There are actually four questions here dealing with issues from 'superweeds' to biodiversity. Will there be an impact? Evidence suggests that it probably won't but that there will certainly be some cases which will cause concern. Finally there's a look at gene flow management with an outline of a range of methods that could work.

This is a very readable account of some of the issues surrounding domesticated and wild crops. It puts forward a good case, well argued. That the result is not clear cut is down to the nature of the material rather than the exposition of the case. A good text to read as background for any work on this topic although the level of detail precludes beginners making it a suitable text for educator or undergraduate.