Genetic analysis of a major international collection of cultivated apple varieties reveals previously unknown historic heteroploid and inbred relationships

Domesticated apple (Malus x domestica Borkh.) is a major global crop and the genetic diversity held within the pool of cultivated varieties is important for the development of future cultivars. The aim of this study was to investigate the diversity held within the domesticated form, through the analysis of a major international germplasm collection of cultivated varieties, the UK National Fruit Collection, consisting of over 2,000 selections of named cultivars and seedling varieties. We utilised Diversity Array Technology (DArT) markers to assess the genetic diversity within the collection. Clustering attempts, using the software STRUCTURE revealed that the accessions formed a complex and historically admixed group for which clear clustering was challenging. Comparison of accessions using the Jaccard similarity coefficient allowed us to identify clonal and duplicate material as well as revealing pairs and groups that appeared more closely related than a standard parent-offspring or full-sibling relations. From further investigation, we were able to propose a number of new pedigrees, which revealed that some historically important cultivars were more closely related than previously documented and that some of them were partially inbred. We were also able to elucidate a number of parent-offspring relationships that had resulted in a number of important polyploid cultivars. This included reuniting polyploid cultivars that in some cases dated as far back as the 18th century, with diploid parents that potentially date back as far as the 13th century

La banane : de son origine à sa commercialisation

Banana: from origin to market. Cultivated bananas are giant herbaceous plants within the genus Musa. They are both sterile and parthenocarpic. There are well over a thousand domesticated Musa cultivars, they are mostly triploid (a few are diploid or tetraploid) and are derived from crosses between two wild species, Musa acuminata and Musa balbisiana. In terms of production, bananas are the fourth agricultural product after rice, wheat, and maize. They constitute the basis of food security for many people. Cropping systems vary widely around the world and contrasting objectives are encountered: consumption by the producer, sale on local or national markets, export, etc. Cooking bananas, including plantains, must be distinguished from dessert bananas, which constitute a major international trade. This international trade started only in the early 1900s but it has since grown continuously. Banana is currently the most exported fruit, in terms of both value and quantity. Despite the high genetic diversity found within the genus Musa, the export market is mainly based on single Cavendish. There are major challenges to banana production from biotic or abiotic stresses to continue to meet the criteria of sustainability, quality and yield that are imposed

SNP development and genetic diversity of the non-native tree Robinia Pseudoacacia in Belgium

National audienc

Evolution de la chalarose du frêne en Wallonie

Depuis quelques années, la maladie du frêne, la chalarose, cause des dégâts catastrophiques dans les frênaies européennes, au point de poser la question de l'avenir du frêne. Avec cet article, l'Observatoire wallon de la santé des forêts fait le point sur la situation en Wallonie et propose des voies de gestion des peuplements affectés par cette maladie

No evidence for genetic differentiation between French and Belgian populations of the exotic tree Robinia pseudoacacia

National audienc

Towards sustainable food systems: the concept of agroecology and how it questions current research practices. A review

Introduction. Multiple environmental and socio-economic indicators show that our current agriculture and the organization of the food system need to be revised. Agroecology has been proposed as a promising concept for achieving greater sustainability. This paper offers an overview and discussion of the concept based on existing literature and case studies, and explores the way it questions our current research approaches and education paradigms. Literature. In order to improve the sustainability of agriculture, the use of external and chemical inputs needs to be minimized. Agroecological farming practices seek to optimize ecological processes, thus minimizing the need for external inputs by providing an array of ecosystem services. Implementing such practices challenges the current structure of the food system, which has been criticized for its lack of social relevance and economic viability. An agroecological approach includes all stakeholders, from field to fork, in the discussion, design and development of future food systems. This inclusion of various disciplines and stakeholders raises issues about scientists and their research practices, as well as about the education of the next generation of scientists. Conclusions. Agroecology is based on the concept that agricultural practices and food systems cannot be dissociated because they belong to the same natural and socio-economic context. Clearly, agroecology is not a silver-bullet, but its principles can serve as avenues for rethinking the current approaches towards achieving greater sustainability. Adapting research approaches in line with indicators that promote inter- and transdisciplinary research is essential if progress is to be made

Lessons learned from the virus indexing of Musa germplasm: insights from a multiyear collaboration

The Bioversity International Transit Center (ITC) for banana hosts more than 1500 accessions largely covering the genetic diversity of the genus Musa. Its objective is to conserve this genetic diversity and to supply plant materials to users worldwide. All the Musa accessions must be tested for virus presence and, if infected, virus elimination must be attempted, to enable the supply of virus-free plant material. An international collaborative effort launched under the auspices of Bioversity International (2007–2013) finally led to the implementation of a two-step process to test the accessions. The first step, called pre-indexing, involved only molecular tests and was designed as a pre-screen of new germplasm lines or existing accessions to reduce the need for post-entry virus therapy and repeated virus indexing. The second step, called full indexing, was performed on either older existing accessions or newer accessions which tested negative during pre-indexing, and involved molecular tests, transmission electron microscopy (TEM) and symptom observation. In total, 270 germplasm lines (434 samples) were pre-indexed; while full indexing was carried out on 243 accessions (68 of which had been pre-indexed). A significant proportion of the samples tested during pre-indexing was infected with at least one virus (68%), showing the utility of this early pre-screening step. Banana streak OL virus and Banana mild mosaic virus were the most commonly detected viruses during both pre- and full indexing. For 22 accessions, viral particles were observed by TEM in full indexing while the molecular tests were negative, underlining the importance of combining various detection techniques. After full indexing, viruses were not detected in 166 accessions, which were then released for international distribution from the ITC. This publication exemplifies how the practical application of diagnostic protocols can raise fundamental questions related to their appropriate use in routine practice and the need for their continuous monitoring and improvement after their first publication