Unravelling the knot of disease resistant hybrid kinship

Within the FEM grapevine breeding program, re-established in the middle ’80s, the selection process has been based on the major need for innovation raised by grapevine growers. During the past years, this request has been addressed to increase the complexity and the originality of wines, while in the last decade the need for new varieties resistant/tolerant to abiotic and biotic stresses has emerged. In order to reach this goal, the germplasm collection has grown, increasing its number of acquisitions. In this work, 264 accessions acquired from European and non-European breeding programs or wild accessions collected in northeastern America were studied. Most were phenotyped for downy and powdery mildew resistance, while all were genetically characterized at 190 microsatellite markers well-scattered across the grapevine genome. Firstly, 9 reference markers were used for the true-to-type identification through international and private databases, where feasible. Secondly, in order to validate the available pedigree information and to infer new relationships, the 50 most informative microsatellite markers were chosen and analyzed with specialized software. Finally, the overall genetic material was divided into five classes: known and related (38%); unknown and related (21%); known and unrelated (10%); unknown and unrelated (23%); and redundant (8%). The unknown (related and unrelated) accessions hold great potential as exclusive genetic resources, mainly donors of disease resistance traits, and will provide preparatory information to prospective Marker-Assisted Breeding programs.