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One of the main concerns about the commercial release of transgenic crops is the likelihood of transgene spread from cultivated species into wild relatives. This question is relevant for oilseed rape/canola (Brassica napus, AACC, 2n=38), as this species is partially allogamous with several wild relatives that are often sympatric with oilseed rape production. A workshop sponsored by the European Science Foundation (11-13 June 2001, Rennes, France) was held: (i) to identify the main weeds present in European and North American countries; (ii) to review results on the ability of oilseed rape to hybridize and backcross with wild relatives; (iii) to review the usefulness and limitations of the tools available for monitoring interspecific hybridization and gene introgression; and (iv) to provide recent results on modelling of gene flow.

Final germination percentages of 25 accessions of Brassicaceae from the UPM (Universidad Politécnica de Madrid) seed bank were evaluated after 38-40 years of storage. The seeds were preserved at temperatures between-5°C and-10°C in flame sealed vials containing dehydrated (blue) silica gel. Seed moisture content ranged between 0.3 and 3% (f.w.b) after storage. Most accessions (ten out of twelve) with high initial (before storage) germination rate (low initial dormancy) maintained these high values almost intact after storage (91-100% germination). In two accessions, seeds had developed a secondary dormancy, which was successfully overcome by scarification. A second set of 13 accessions had low initial germination rates (0-20%, i.e. high initial dormancy). In one accession, dormancy had been broken during storage (92% germination) and in nine accessions germination was significantly enhanced by GA 3 and or scarification. Seed dormancy most often decreases during storage but it may also increase or remain unchanged. The consideration of these dormancy variations is very important when evaluating seed longevity in wild species. The preservation method based on silica gel and low temperature (-5°C and-10°C) has proved highly efficient at least for Brassicaceae. Vials with seeds of 12 additional accesssions had remained at room temperature during 34-39 years and those seeds showed germination percentages that were similar to those preserved in the cold room. This result suggests that temperature might not be as important as expected-at least for medium-term preservation-and supports the possibility of using ultra-dry methods.

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Thirty-two differential characters are numerically analysed for the six existing taxa of the genus Vella L. The closely related monotypic genus Boleum Desv. is also included for comparison. Most of the characters used are morphological, but cariological, ecological and biogeographical aspects have also been studied. The results indicate that four distinct species, one (V. pseudocytisus L.) with three sub-species, should be distinguished. The new combination V. anremerica (Lit. et Maire) Gomez-Campo (basionym: V. pseudocytisus L. subsp. anremerica Lit. et Maire) and the new name V. pseudocytisus L. subsp. paui Gomez-Campo for V. pseudocytisus L. var. glabrescens Willk., nomen nudum are presented.A key is given to aid identification of these taxa. Their conservation status is also discussed.

For plant species with orthodox seeds, seed banks provide the most practical method for preserving large amounts of genetic material in a small space. The ultimate goal is seed preservation for several centuries, or perhaps even millennia. Paradoxically, seed banking practices can induce high levels of internal genetic erosion, starting with the sampling process and following through all the remaining processes: initial or periodic germination tests, distribution, regeneration, etc. These may appear quite normal and necessary operations, but they may also lead to a potentially significant waste of material when conducted without sufficient attention to detail, or without a minimal sense of economy. Defective seed preservation methods have been, by far, the main cause of massive losses of valuable material, and thus of genetic erosion. The first seed bank in the world was created in St. Petersburg (Petrograd at that time, soon after renamed Leningrad, in the former USSR) in the 1920s. It was intended initially to preserve the important material collected by N.I. Vavilov during c. 100 collecting missions in 64 countries (Anonymous, 2006). However, such a glorious start was soon overshadowed by political and financial problems, which lasted a long time. During the Second World War, the Institut fü r Pflanzengenetik und Kulturpflanzenforschung (IPK) and its genebank were created within the Leibniz Institute in Gatersleben (Germany). With ups and downs during the war and postwar period, this bank actively functioned within the former DDR, and has recently celebrated its sixtieth anniversary. In the 1950s, a third large seed bank was established in Fort Collins (Colorado, USA) by the USDA National Seed Storage

No abstract

Eruca vesicaria subsp. sativa (syn. E. sativa) is a cruciferous vegetable and oilseed crop that is high in erucic acid. It occurs throughout the Mediterranean region and western Asia, and has been naturalized elsewhere as a crop/weed escape. It is closely related to subsp. vesicaria and subsp. pinnatifida, which are endemic to Spain and north-western Africa, respectively. This study evaluated patterns and levels of diversity in the three subspecies based on 234 amplified fragment length polymorphisms (AFLP), and evaluated agronomic and seed quality data in a field trial in western Canada. AFLP data revealed three main clusters: 'Sativa' (33 accessions of subsp. sativa), 'Vesicaria' (nine accessions of subsp. vesicaria) and a 'Pinnatifida' cluster (one accession of subsp. pinnatifida and three Moroccan accessions of subsp. sativa). The Sativa cluster separated into Mediterranean and Asian groups, likely reflecting differences in origin (wild versus cultivated) or primary usage, vegetable versus seed oil. The origin of the introduced Mexican population was confirmed as subsp. sativa. The highest levels of diversity were found in the Sativa cluster (88% AFLP polymorphisms) and the least in the Vesicaria (56%) and Pinnatifida (39%) clusters. Extensive variation was observed among the 159 subsp. sativa accessions evaluated in the field trial, and overall findings indicated a favourable agronomic potential.