Abstract
To answer the new challenges faced by viticulture, grapevine breeding major goal is to create new cultivars integrating both resistance against pathogens and adaptation to climatic changes while still offering high quality final products. These traits have to be accumulated from different sources, several Vitis species for resistance to biotic and abiotic stresses and V. vinifera for quality. Compared to other crops, the genetic bases of the variability of these complex traits are still poorly understood in grapevine, in particular because searching for QTLs in perennial woody species is very long, tedious and costly. Applying association genetics at the whole genome scale (genome-scan) will permit to more rapidly and efficiently identify the main genetic factors underlying the variation of agronomically important traits, by taking advantage of the high variability and recombinations accumulated within the available genetic resources. Precise knowledge of the structure of genetic diversity and linkage disequilibrium (LD) in study samples is crucial to design and perform association genetics studies. The DLVitis project aims at producing this knowledge for 4 Vitis species of interest to breeding, V. vinifera and 3 american species, V. riparia, V. cinerea and V. aestivalis. Its main objectives are : - to characterize the structure of genetic diversity within populations of the 3 American species - to characterize LD between SNPs in 4 genomic regions of 2 Mb each, in 4 samples of V. vinifera and 1 population of each of the 3 American species to locally test genome-scan for two traits, resistance to downy mildew and berry size.