This scientific article provides an insight into the status of public research in genetically modified (GM) crops in Egypt, Kenya, South Africa and Zimbabwe in 2004.

The authors document 54 transgenic 'events' — specific instances of genetic transformation — across the four countries. They identify work to develop GM strains for 20 crops, including cotton, maize, potatoes, sugar cane, tomatoes and wheat. South Africa is shown to be a particularly important centre for biotech research, accounting for 28 out of the 54 events examined.

The authors call for a simplified system to facilitate regulatory approval of GM crop trials and commercial releases across the continent as a whole and suggest measures to encourage inter-institutional links and South–South collaborations.

This paper reports on the successful transfer of a key disease-resistance gene from maize into rice, demonstrating the feasibility of gene transfer between distantly related grasses. The technique has important implications for introducing resistance to diseases in crops with no inherited resistance.

It is important in that it reveals how a single gene can influence resistance to unrelated disease-causing microbes. The gene in question, called Rxo1, controls resistance to bacterial streak disease in rice, as well as bacterial stripe disease in sorghum and maize.

This work is of interest to companies and academic researchers working on diseases of cereal crops, and to policy-makers and research managers because of its implications for the development of disease resistance in some of the world’s major food crops. Overall, it offers an interesting insight into a potentially valuable avenue of research.

This report by US and Chinese researchers analyses the impact of two insect-resistant GM rice varieties grown at eight trial sites in China. The authors studied crop yields, levels of pesticide application and whether farmers growing GM rice varieties reported fewer pesticide-related illnesses than non-GM farmers.

The study was carried out on pre-production trials, with data gathered from randomly selected households. External enumerators surveyed farmers and found that those growing GM rice applied pesticide less frequently than those growing non-GM rice (0.5 times per season as compared with 3.7 times by non-GM farmers). Yields of insect-resistant rice were 6 to 9 per cent higher than non-GM varieties. In addition, no farmer growing GM rice reported adverse health effects. By contrast, 8.3 per cent of farmers in 2002, and 3 per cent in 2003, reported feeling ill after applying pesticide to their non-GM rice crop.

These data on the impact of GM rice in pre-commercial trials are could pave the way for the introduction of other GM crops because the commercialisation of a major GM food crop such as rice is expected to influence the introduction of other GM food crops in the future.

According to the authors of this literature review, there are no innate differences in the potential environmental impact of GM crops compared with non-GM varieties. Crucial questions remain, however, as to what constitutes a "significant", and more importantly, an "acceptable" effect on the environment. Such questions are being asked about GM crops that have not previously been asked about varieties developed by so-called conventional methods.

Altered biodiversity, increased crop pervasiveness, and the effect of toxins such as Bt in soil and water systems are considered, as well as the impact of "free" transgenic DNA in the environment. The authors suggest a case-by-case approach for making decisions about the commercial cultivation of GM crops; the impact of gene transfer from a GM crop to a wild plant relative or other ecosystems will depend on the nature of the gene, as well as the local ecology.

The authors conclude that to minimise the environmental impact of GM crops or new agricultural practices associated with their commercial cultivation, the timing and expression of plant transgenes should be more specific. A wider range of pest resistance mechanisms is also needed to reduce the selective pressure on the pest population. In acknowledging that new and more creative ways of managing crops may be needed, the authors call for incentives that will require GM crops to be combined with other agricultural practices that promote crop and wildlife diversity, as well as soil fertility.

Bt cotton, developed to resist bollworm attack, can have significant economic and environmental benefits, according to a three-year study of hundreds of Chinese smallholder farmers. The study, carried out by collaborators from China and the USA, also revealed that growing Bt cotton can have a positive impact on human health. The main benefits to farmers from using Bt varieties were increased crop yield and reductions in the amount of pesticide used. As well as lower input costs, growers reported fewer pesticide-related illnesses associated with growing Bt cotton, as compared with the non-Bt varieties.

While the authors describe greater chemical use in some areas of China growing Bt cotton, they found no evidence of an associated increase in pesticide resistance within the bollworm population. They believe that the transient increase in pesticide use was due either to changes in pest pressure, or the fact that some farmers were sowing seed saved from the previous year. This could have reduced the effectiveness of the resistant crop variety. Economic theory has correctly predicted that increased supply would result in lower market prices for cotton growers. The authors conclude, however, that current prices still offer considerable economic gains for farmers growing the Bt varieties.

This review gives a valuable insight into the thought processes behind many of the regulatory frameworks in place regarding the safety of foods containing GM ingredients. Starting with the concept of substantial equivalence as a management tool for safety evaluations, it then addresses issues such as allergenicity, unintended effects of a genetic manipulation and risk assessment.

Although broad international consensus exists about the principles of the safety of GM-derived foods, the regulatory frameworks may differ between countries. These are summarised, along with useful data about foods already developed and results of laboratory feeding studies. The authors consider in some detail the challenges associated with such studies, as well as the difficulties in linking an observed effect with a specific food component.

They also suggest that new research tools enabling detailed analysis of sub-cellular components will be significant in helping to identify and characterise any differences between GM products and their non-GM counterparts. According to the authors, an integrated approach using molecular biology, toxicology, genetics and nutritional information is needed, alongside existing long-established techniques used to assess the safety of conventionally-produced foods.

This report reviews some of the genetically engineered products being developed by industry and university scientists and aims to provide an illustrative overview of what could be the "next generation" of genetically engineered agricultural products. It is not intended to endorse these future applications, but rather to help inform the debate on the broader public policy issues raised by agricultural biotechnology. The report is highly readable, well illustrated and explains the technology clearly to the non-specialist reader.