Les plantes parentes des espèces cultivées, un réservoir de biodiversité pour l’amélioration: l’exemple des Daucus

The parents plants of cultivated species, a wealth of biodiversity for improvement : Daucus spp. as an example - We are dealing here with a biodiversity which is often somewhat forgotten, that of the parent plants of cultivated species. This type of biodiversity gathers together within the same whole group, taxa descended from the natural flora, others coming from domestication as well as taxa of an intermediate category (cultivated plants having gone wild or having become naturalized, wild-cultivated hybrids, and so on). A programme dedicated to the carrot (Daucus carota L.) on the French territory is briefly described. It comprises phases of preliminary analyses (literature, herbaria, local botanists), of prospection, comparative cultivation, DNA analyses (microsatellites) so as to draw up the genetic structuring of that set, and also some advice for conservation and the study of resistance to parasites

The Daucus carota complex in France: advancement of research, focus on Mediterranean situation

A pluridisciplinary research program has been going on for several years on the Daucus carota L. complex in France. Many field studies were made for both inland and coastal populations. More than 100 populations were visited, studied in their biotopes, gathered and comparatively cultivated. The following disciplines were then applied: - adult plant morphology, - seedling morphology, - floral biology, - genetics (microsatellite), - agronomical tests (controlled hybridizations, resistance against pests and diseases...). Preliminary first results mainly concerning the Mediterranean flora are presented. Within the subgroup gummifer, the Atlantic and Mediterranean entities must be kept separate; on the Atlantic coast, the North-West group and the Basque group are genetically distinct. All the Corsican populations visited are genetically distinct from all others studied, including those of the continental Mediterranean seashore of France. A focus is made on subsp. maritimus and subsp. hispanicus and their situation is discussed

Genetic diversity and taxonomic aspects of wild carrot in France

If in France, genetic resources of cultivated carrot are well studied and preserved, the wild compartment of the species remains unknown and underutilized, while there are many populations of wild carrot on the French territory. Several collecting missions were undertaken from 2009 to 2013 to identify and collect populations, particularly in coastal areas, in continental France and Corsica. More than a hundred populations were collected, with a good distribution throughout the territory, and eleven taxa were identified. The status of these taxa is variable, with some very common and others underrepresented or specific to a given area. Morphological and molecular studies are developed in order to improve the knowledge of taxonomy and diversity. The study conducted with microsatellite markers showed a high genetic diversity at the intra-and inter-populations levels. The overall results show that the Mediterranean coast and Corsica exhibit a particularly high diversity. The work confirms the specific interest of some populations and the taxonomic separation into 2 subgroups carota and gummifer in Daucus carota L. This study will allow developing a strategy for management of genetic resources and their valorisation in breeding

Le compartiment sauvage de la carotte en France : des ressources génétiques importantes et pourtant méconnues

La France est considérée comme centre secondaire de diversification de la carotte, du fait de l’activité importante de sélection (par des maraîchers ou semenciers), ce qui justifie les actions de conservation et connaissance des variétés anciennes menées par le réseau de ressources génétiques « Carotte et autres Daucus ». Par contre, le compartiment sauvage est méconnu et sous-exploité, alors qu’il s’agit d’une espèce pour laquelle de nombreuses populations existent sur le territoire français, avec une situation très contrastée. Si la carotte sauvage D. carota spp carota n’est pas en danger, d’autres sous espèces sont protégées (ssp gadecaei) ou menacées du fait de la dégradation de leur milieux naturels notamment en zone littorale ou de possibles introgressions avec la sous-espèce carota. Le travail présenté porte donc sur : i/ la sauvegarde et la mise à disposition des ressources génétiques sauvages, à travers l’inventaire de populations in situ et la constitution de collections ex-situ ; ii/ l’approfondissement de la connaissance et de l’identification taxonomique des sous-espèces sauvages ; iii/ la connaissance de la diversité au sein du compartiment sauvage (marqueurs SSR et données écologiques) ; et iv/ l’évaluation des ressources génétiques sauvages de carotte pour permettre leur exploitation (fertilité, croisements avec le compartiment cultivé, tolérance à différents bioagresseurs). Ce programme fait l’objet du soutien d’un contrat de branche du ministère de l’agriculture et implique les membres du réseau « Carotte et autres Daucus ».