Genetic diversity, linkage disequilibrium and power of a large grapevine (Vitis vinifera L) diversity panel newly designed for association studies

UMR-AGAP Equipe DAVV (Diversité, adaptation et amélioration de la vigne) ; équipe ID (Intégration de Données)International audienceAbstractBackgroundAs for many crops, new high-quality grapevine varieties requiring less pesticide and adapted to climate change are needed. In perennial species, breeding is a long process which can be speeded up by gaining knowledge about quantitative trait loci linked to agronomic traits variation. However, due to the long juvenile period of these species, establishing numerous highly recombinant populations for high resolution mapping is both costly and time-consuming. Genome wide association studies in germplasm panels is an alternative method of choice, since it allows identifying the main quantitative trait loci with high resolution by exploiting past recombination events between cultivars. Such studies require adequate panel design to represent most of the available genetic and phenotypic diversity. Assessing linkage disequilibrium extent and panel power is also needed to determine the marker density required for association studies.ResultsStarting from the largest grapevine collection worldwide maintained in Vassal (France), we designed a diversity panel of 279 cultivars with limited relatedness, reflecting the low structuration in three genetic pools resulting from different uses (table vs wine) and geographical origin (East vs West), and including the major founders of modern cultivars. With 20 simple sequence repeat markers and five quantitative traits, we showed that our panel adequately captured most of the genetic and phenotypic diversity existing within the entire Vassal collection. To assess linkage disequilibrium extent and panel power, we genotyped single nucleotide polymorphisms: 372 over four genomic regions and 129 distributed over the whole genome. Linkage disequilibrium, measured by correlation corrected for kinship, reached 0.2 for a physical distance between 9 and 458 Kb depending on genetic pool and genomic region, with varying size of linkage disequilibrium blocks. This panel achieved reasonable power to detect associations between traits with high broad-sense heritability (> 0.7) and causal loci with intermediate allelic frequency and strong effect (explaining > 10 % of total variance).ConclusionsOur association panel constitutes a new, highly valuable resource for genetic association studies in grapevine, and deserves dissemination to diverse field and greenhouse trials to gain more insight into the genetic control of many agronomic traits and their interaction with the environment

Inventaire en horticulture ornementale des solutions proposées par l'Inra pour réduire l'impact des systèmes agricoles sur l'environnement rapport pour l'INRA (à la demande de Marion Guillou, Directrice générale)

Inventaire en horticulture ornementale des solutions proposées par l'Inra pour réduire l'impact des systèmes agricoles sur l'environnemen

La recherche et l'enseignement

National audienc

La recherche et l'enseignement

National audienc

La recherche et l'enseignement

National audienc

Interspecific crosses between Pelargonium x hortorum and P. quinquelobatum using embryo rescue and molecular characterization of hybrids by an endogenous chs probe

Interspecific hybridizations were performed between Pelargonium x hortorum (subgenus Ciconium) and a yellow-flowered species, Pelargonium quinquelobatum (subgenus Eumorpha). Hybrids, using embryo rescue. were obtained only when P. quinquelobatum was used as the female parent. A polymerase chain reaction (PCR) cloned Pelargonium chs gene fragment was used as probe to characterize hybrids by restriction fragment length polymorphism (RFLP) analysis. Chromatographic flavonoid analysis showed that hybrids could synthesize both flavonol glycosides and anthocyanin in the petals which were pale yellow to pale pink from the proximal to the distal part

Multiplication du platane par bouturage hivernal sur couche et microbouturage in vitro

Le platane est un arbre très utilisé dans le Sud de la France pour son aspect décoratif et pratique (ombrage). Sa culture est menacée par le chancre coloré, Ceratocystis fimbriata f. sp platani d'où l'intérêt de sélectionner des plantes résistantes à ce pathogène. Afin de disposer d'un nombre de plantes en quantité suffisante, une technique de multiplication efficace s'avère nécessaire. Deux techniques sont décrites: le bouturage hivernal mais qui est limité dans le temps et le microbouturage in vitro qui permet de produire des plantes régulièrement selon la demande. Il est à noter que les milieux de culture doivent être ajustés au niveau des macro microéléments et des concentrations en hormones de croissance en fonction des espèces ou clones testés pour obtenir une efficacité maximale. Dans le cas de notre étude, le milieu WPM (Woody Plant medium) présente un spectre d'action plus large que le milieu MS. (Résumé d'auteur