When first I opened Jonny Gressel's ‘Genetic Glass Ceilings’ I wondered for whom he had written it. I soon found out – it was for me.

As a microbial biochemist, perhaps even a molecular biologist, for the past 12 years or more involved with agricultural biotechnology, I am familiar enough with the science but know well that my exposure to real life agriculture with all its opportunities and problems is limited. What Professor Gressel did for me was to provide the practical and realistic context for the genetics which is the focus of his book, showing how many of the problems associated with improving crop plants which will have to be addressed in the coming years are beyond the scope of conventional breeding, even in its most developed and sophisticated forms. He foresees an increasing dependency on the flexibility and power of transgenesis, moving genes between organisms which are not necessarily closely related.

His central thesis is that conventional breeding methods, essentially the shuffling of genes between close relatives with selection for the most desirable combinations, are nearing the end of what can be achieved. Not only can such breeding be very slow and drawn out, especially when recessive properties are being sought, but also many crop traits which would be highly desirable are not attainable because the appropriate genes simply do not exist within the accessible gene pool of cross-breeding relatives. That is the genetic glass ceiling of the book's title. Further improvements can be achieved only by bringing in the appropriate genes from more distant plants which cannot cross-breed conventionally with the target variety. Much more then becomes possible.

We face mounting pressure on agriculture from an increasing global population, more demand for non-food products (notably biofuels), uncertainties about our future climate plus – as if those were not enough – a growing demand for more meat in their diet from tens or indeed hundreds of millions of people in the poorer countries who have hitherto been unable to afford it. Moreover, all that has to happen more or less within the existing confines of agricultural land so as not to encroach on wilderness and forest even while those agricultural acreages themselves are being eroded by urban expansion. To the problems of improving agricultural productivity and the quantity of food produced, there is also the matter of spoilage during often inadequate storage conditions; in some cases that, too, might be addressed by modifying the crops transgenically, mainly to confer resistance to insects. It is in that broad context that we need agricultural productivity to be maximized, with genetics a major but not, of course, the only contributor.

About one-third of the book deals with basic considerations of transgenic technology, including biosafety. Dr Gressel makes a strong case against regulation of the process by which a crop is derived rather than the properties of the crop variety itself, an approach to regulation which, in the European Union in particular, means that the way a crop plant has been bred becomes all-important, never mind that the crop does what is needed without problems. Such a highly restrictive approach and the political way in which it is applied makes the approval of new crops in Europe close to (but not quite) impossible. Each new trait has to be evaluated separately so that many potentially valuable developments are, for the moment at least, simply not undertaken because they are just not worth the uncertainty and the hassle in view of the sizes of their potential markets.

The promise is what could be done in a more sympathetic regulatory regime to improve a variety of crops which have value but, unlike maize, soybeans, wheat and rice, have not made it into the big league of food crops: crops like tef, buckwheat, sorghum and others for which the cost of development are too high and the commercial returns too uncertain in the existing complex regulatory environment. Some two-third of the book is an in-depth analysis of those crops and others to explore what might be done to improve them using the best means at our disposal.

The book is indeed an eye-opener but not entirely an easy read: when discussing individual crops and possibilities, in particular, there is a good deal of detail demanding close attention. But it is well worth the effort: it has helped me enormously to integrate my existing scientific understanding into the practical world of agriculture so that I can begin to see for myself just why transgenic technology is so important and offers so many practical benefits that will be essential for feeding the world's burgeoning population in the coming decades.