Genealogy investigation in over 2300 grapevine cultivars (Vitis vinifera L.)
Résumé
Since 1997, many studies based on the inheritance of nuclear microsatellite markers to verify or uncover the parentage of grapevine cultivars have been performed. The aim of the present study was to undertake an extended analysis using a large sample of Vitis vinifera cultivars held in the INRA “Domaine de Vassal” Grape Germplasm Repository (F-34340 Marseillan-Plage, France). We genotyped 5516 accessions with 20 nuclear SSR markers and checked their identity. The dataset of 2332 unique genotypes identified (without mutants) was analysed using FaMoz software. Parentages showing a LOD score higher than 18 were validated in relation to historical data. During the process of creating the unique genotype table, we identified or confirmed approximately170 cases of cultivars displaying a mutation, mainly for berry skin colour but also for other traits such as leaf characteristics, flower sex, and ploidy level. The parentage analysis first permitted us to identify the full parentage of approximately 710 genotypes resulting in i) confirmations of the pedigree as stated by the breeder (180) or in previous published studies (80), ii) partial or complete invalidations of published pedigree (90), or iii) original discoveries (390). Second, in approximately 1150 genotypes, only incomplete parentages could be determined due to the absence of complementary parents in the cultivar sample. Last, in 284 genotypes, no direct relationship with another cultivar in the collection was revealed. Compiling these parentage results improves our knowledge of the genetic constitution of the V. vinifera cultivars and the identification of the main progenitors involved in varietal assortment, evolution, and grapevine breeding.