The loss of variation in crops due to the modernization of agriculture has been described as genetic erosion. The current paper discusses the different views that exist on the concept of genetic erosion in crops. Genetic erosion of cultivated diversity is reflected in a modernization bottleneck in the diversity levels that occurred during the history of the crop. Two stages in this bottleneck are recognized: the initial replacement of landraces by modern cultivars; and further trends in diversity as a consequence of modern breeding practices. Genetic erosion may occur at three levels of integration: crop, variety and allele. The different approaches in the recent literature to measure genetic erosion in crops are reviewed. Genetic erosion as reflected in a reduction of allelic evenness and richness appears to be the most useful definition, but has to be viewed in conjunction with events at variety level. According to the reviewed literature, the most likely scenario of diversity trends during modernization is the following: a reduction in diversity due to the replacement of landraces by modern cultivars, but no further reduction after this replacement has been completed.

In recent years, an increasing number of papers has been published on the genetic diversity trends in crop cultivars released in the last century using a variety of molecular techniques. No clear general trends in diversity have emerged from these studies. Meta analytical techniques, using a study weight adapted for use with diversity indices, were applied to analyze these studies. In the meta analysis, 44 published papers were used, addressing diversity trends in released crop varieties in the twentieth century for eight different field crops, wheat being the most represented. The meta analysis demonstrated that overall in the long run no substantial reduction in the regional diversity of crop varieties released by plant breeders has taken place. A significant reduction of 6% in diversity in the 1960s as compared with the diversity in the 1950s was observed. Indications are that after the 1960s and 1970s breeders have been able to again increase the diversity in released varieties. Thus, a gradual narrowing of the genetic base of the varieties released by breeders could not be observed. Separate analyses for wheat and the group of other field crops and separate analyses on the basis of regions all showed similar trends in diversity.

The Mr 28.000 crystal protein gene of Bacillus thuringiensis subspecies israelensis has been cloned into pBR322 as part of a 9.7 kb HindIII fragment. From hybridization experiments of recombinant p425 DNA with B.t. subspecies israelensis RNA from different stages of growth it was concluded that transcription of the gene is restricted to early sporulation stages. Nucleotide sequence analysis revealed the presence of a large open reading frame with a coding capacity of 249 amino acids (Mr 27.340). Nuclease S1 mapping demonstrated that transcription starts 44 nucleotides upstream of the initiation codon. A Shine-Dalgarno sequence (AAGGAG) was found 10 nucleotides upstream of the translation startpoint. At the 3'-end of the gene a complex secondary structure was found immediately after the stop-codon. Despite the presence of these regulation signals only limited expression in E. coli was detected. This can be explained by assuming that B.t. subsp. israelensis promotor sequences are poorly recognized by E. coli RNA polymerase.

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Biobanks correspond to different situations: research and technological development, medical diagnosis or therapeutic activities. Their status is not clearly defined. We aimed to investigate human biobanking in Europe, particularly in relation to organisational, economic and ethical issues in various national contexts. Data from a survey in six EU countries (France, Germany, the Netherlands, Portugal, Spain and the UK) were collected as part of a European Research Project examining human and non-human biobanking (EUROGENBANK, coordinated by Professor JC Galloux). A total of 147 institutions concerned with biobanking of human samples and data were investigated by questionnaires and interviews. Most institutions surveyed belong to the public or private non-profit-making sectors, which have a key role in biobanking. This activity is increasing in all countries because few samples are discarded and genetic research is proliferating. Collections vary in size, many being small and only a few very large. Their purpose is often research, or research and healthcare, mostly in the context of disease studies. A specific budget is very rarely allocated to biobanking and costs are not often evaluated. Samples are usually provided free of charge and gifts and exchanges are the common rule. Good practice guidelines are generally followed and quality controls are performed but quality procedures are not always clearly explained. Associated data are usually computerised (identified or identifiable samples). Biobankers generally favour centralisation of data rather than of samples. Legal and ethical harmonisation within Europe is considered likely to facilitate international collaboration. We propose a series of recommendations and suggestions arising from the EUROGENBANK project.

Current farmers' breeding goes beyond the gradual selection in landraces, and includes development and maintenance of major new farmers' varieties that are rather uniform, in particular in South-East Asia. Modern varieties developed in the formal sector have simply replaced landraces as the source of diversity, but have not abolished farmers' breeding practices. Interpretations of the new international agreements on plant genetic resources should protect the development of modern farmers' varieties. However, ensuring recognition of collective innovation, allowing access to relevant germplasm sources for farmers' breeding activities, keeping materials freely available, and arranging for effective benefit sharing, all form major challenges. This paper proposes a new protective measure: namely "origin recognition rights."

Cecropin B is a small antibacterial peptide from the giant silkmoth Hyalophora cecropia. To reveal the potential of this peptide for engineering bacterial disease resistance into crops, several cecropin B gene constructs were made either for expression in the cytosol or for secretion. All constructs were cloned in a plant expression vector and introduced in tobacco via Agrobacterium tumefaciens. A cDNA-derived cecropin B gene construct lacking the amino-terminal signal peptide was poorly expressed in transgenic plants at the mRNA level, whereas plants harbouring a full-length cDNA-derived construct containing the insect signal peptide, showed increased cecropin B-mRNA levels. Highest expression was found in plants harbouring a construct with a plant-gene-derived signal peptide. In none of the transgenic plants could the cecropin B peptide be detected. This is most likely caused by breakdown of the peptide by plant endogenous proteases, since a chemically synthesized cecropin B peptide was degraded within seconds in various plant cell extracts. This degradation could be prevented by the addition of specific protease inhibitors and by boiling the extract prior to adding the peptide. In addition, anionic detergents, in contrast to cationic, zwitter-ionic or non-ionic detergents, could prevent this degradation. Nevertheless, transgenic tobacco plants were evaluated for resistance to Pseudomonas solanacearum, the causal agent of bacterial wilt of many crops, and P. syringae pv. tabaci, the causal agent of bacterial wildfire, which are highly susceptible to cecropin B in vitro. No resistance was found. These experiments indicate that introduction and expression of cecropin B genes in tobacco does not result in detectable cecropin B protein levels and resistance to bacterial infections, most likely due to degradation of the protein by endogenous proteases.

Enset [Ensete ventricosum (Welw.) Cheesman] is a major multi‐purpose crop in Ethiopia, which has been identified as the center of origin and diversity of enset. During the last decades, the local farming systems in which enset is maintained have become endangered. Conservation of clonally propagated crops like enset is complex and relatively expensive. Consequently, an assessment of clonal diversity is essential in order to maximize conservation efforts. In the present study, 146 clones from five different regions in southern and southwestern Ethiopia were characterized with amplified fragment length polymorphisms (AFLPs) to investigate genetic relationships among clones, identify duplicates, and study regional variation. A total of 180 bands were scored, of which 104 (58%) appeared polymorphic. Twenty‐one duplication groups consisting of 58 clones were identified. Duplicates were related to different utilization purposes of clones and to the changing of vernacular names after exchange of clones between communities. Despite large variation in agroecological conditions among regions, only 4.8% of the total genetic variation was found between regions, whereas 95.2% was found within regions. This finding may be explained by regular long distance exchange of clones. Furthermore, it suggests the existence of substantial levels of phenotypic plasticity in enset. The results of the study allow for a substantial and well based reduction of the number of clones qualifying for conservation. In addition, the exchange between regions suggested by this study indicates that unexplored additional diversity, if existing, should mainly occur in divergent farming systems.