Identity and parentage of two alpine grape cultivars from Switzerland (<i>Vitis vinifera</i> L. Lafnetscha and Himbertscha)

Abstract

Four closely related white grape cultivars from the Western Alps (Switzerland) - Humagne Blanc, Completer, Lafnetscha and Himbertscha - and three putative relatives or synonyms - Gouais Blanc, Plantscher and Bordeaux Blanc - were analyzed with up to 50 microsatellite markers. Humagne Blanc and Completer are ancient cultivars from the Haut-Valais and Graubünden regions, respectively. Lafnetscha and Himbertscha are lesser-known cultivars scarcely cultivated in Haut-Valais. Lafnetscha is frequently considered as synonym of Completer. Himbertscha might be related to Gouais Blanc, one of the parents of Chardonnay, Gamay, etc. Plantscher, a putative synonym of Lafnetscha, is scarcely cultivated in Haut-Valais (Switzerland) and Bordeaux Blanc (or Gros Bourgogne) is a cultivar of unknown origin (despite its names) cultivated in Switzerland. Our results allowed us to determine the true-to-type Lafnetscha and confirmed that Lafnetscha is not a synonym of Completer. Plantscher is not a synonym of Lafnetscha but a synonym of Bordeaux Blanc (or Gros Bourgogne) and is a likely parent or progeny of the Hungarian Furmint. Himbertscha is not related to Gouais Blanc and shares at least one allele at each locus with Humagne Blanc, providing strong evidence of a parent/progeny relationship. Given that Humagne Blanc is an older cultivar, we propose that it is the parent of Himbertscha. Alleles at 49 out of 50 microsatellite loci are consistent with Lafnetscha being the progeny of Completer and Humagne Blanc. The exception is a 10-base pair discrepancy at one locus (VVMD 36), most likely due to the occurrence of a null allele, since this parentage is supported at other markers by very high likelihood ratios. With Lafnetscha = Completer x Humagne Blanc, we present the second grape cultivar parentage showing a multiple repeat discrepancy at one locus. This study emphasizes that one multiple repeat unit discrepancy is not sufficient to reject a parentage, and that the greater is the number of loci, the greater are the chances to encounter null alleles or clonal mutations.