In the towns of Bento Gonçalves, RS, and Jales, SP, in the greenhouse and field, respectively, was determined the degree of Oidium infection in the collection of grapevine cultivars of the EMBRAPA/Grapevine and Wine Research Center. The criterions used to estimate the affection were in accordance with distinctive mark proposed by IPGRI/UPOV/OIV (1997). The comparation with the susceptibles Vitis vinifera 'Thompson Seedless' and 'Itália' shows the existence of many genotypes of hybrids cultivars and americans wild species with Oidium resistance. The greenhouse environment is more adequate to determine the resistance characteristics of the varieties investigated.
Plant improvement; Oidium, Uncinula necator; Oidium tuckeri
