ARS | Publication request: Investigations into the origin of 'Norton' grape using SSR markers

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 25, 2009
Publication Date: March 1, 2010
Citation: Stover, E.W., Dangl, G., Yang, J., Bautista, J.C., Aradhya, M.K. 2010. Investigations into the origin of 'Norton' grape using SSR markers. Proceedings of Florida State Horticultural Society. 122:19-24.

Interpretive Summary: The ‘Norton’ grape (also known as 'Cynthiana') produces excellent wine in some regions where Vitis vinifera (the European grape used for most wine worldwide) is difficult to grow, with wines often indistiguishable from those made with vinifera grapes. Regions where 'Norton' is grown include the SE, Midwest, and Mid-Atlantic regions of the US where resistance to fungal diseases and/or tolernace to Pierce's disease make it very useful. The high-quality and disease resistance of ‘Norton’ make it attractive to generate hybrids of similar parentage, producing cultivars with traits distinct from ‘Norton’ but with similar disease resistance and high quality. ‘Norton’ is frequently described as being the species V. aestivalis, which is a purely N. American grape but when discovered was initially described as a hybrid between an American grape (‘Bland’) and a V. vinifera grape (‘Miller’s Burgundy’, a synonym for ‘Pinot Meunier’). To try to identify the parents of ‘Norton’, DNA tests called simple sequence repeat (SSR) markers were compared across V. vinifera cultivars and accessions derived from American species. The precise parentage could not be identified using available data. Gene variant frequencies were compared among 181 grapes of N. American origin and 354 V. vinifera cultivars for which there were data at 13 different genes. At least one ‘Norton’ gene variant (there are two for every SSR gene used) at all 13 genes was present among the vinifera cultivars, while at 6 genes the other ‘Norton’ gene variant did not occur among the vinifera cultivars, suggesting these were likely from a non-vinifera parent. Statistical analysis of gene variants for different Vitis species groups indicated that the likley non-vinifera ‘Norton’ gene variants were most common within the group which includes the species Vitis aestivalis. These results are consistent with ‘Norton’ being a V. vinifera x V. aestivalis hybrid, but do not provide absolute proof. ‘Norton’ gene variants for one SSR gene (VVMD36) are very rare and should help in identifying ‘Norton’ parents since these gene variants are found in so few grape types. Interestingly, the vinifera grape cultivar ‘Enfariné Noir’, shares the rare as well as most common gene variants with the presumed ‘Norton’ vinifera parent, suggesting it may be a grandparent of 'Norton'. ‘Enfariné Noir’ has similarities with ‘Pinot Meunier’ in alternate naming (many old grapes have more than a dozen names and ‘Pinot Meunier’ is also known as ‘Enfariné'), appearance of fruit (both grape types look like they are dusted with flour, which is reflected in their names) and both originate in the Burgundy region of France. It would not be surprising if ‘Enfariné Noir’ or a seedling from this cultivar were growing in Virginia in the early 1800s when 'Norton' was first discovered, and due to similarities was mistakenly assumed to be the common 'Miller's Burgundy' grape.

Technical Abstract: ‘Norton’ produces excellent wine in some regions where Vitis vinifera is difficult to grow. The high-quality and disease resistance of ‘Norton’ make it attractive to generate hybrids of similar parentage, producing cultivars with traits distinct from ‘Norton’ but with similar adaptation. ‘Norton’ is frequently described as V. aestivalis, but was initially declared a hybrid between an American grape (‘Bland’) and V. vinifera (‘Miller’s Burgundy’, a synonym for ‘Pinot Meunier’). To try to identify the parents of ‘Norton’, simple sequence repeat (SSR) markers were compared across V. vinifera cultivars and accessions derived from American species. The precise parentage could not be identified using available data. Allele frequencies were compared among 181 Euvitis of N. American origin and 354 V. vinifera cultivars for which there were data at 13 loci. At least one ‘Norton’ allele at all 13 loci was present among the vinifera cultivars, while at 6 loci the other ‘Norton’ allele did not occur among the vinifera cultivars, suggesting these alleles were likely from a non-vinifera parent. Allelic frequency distributions for different Vitis series indicated that the putative non-vinifera ‘Norton’ alleles were most common within the aestivales. These data are consistent with ‘Norton’ being a V. vinifera x V. aestivalis hybrid. ‘Norton’ alleles for locus VVMD36 are rare and offer the best opportunity for identifying ‘Norton’ parents. Interestingly, ‘Enfariné Noir’, a vinifera cultivar which has similarities in synonymy, morphology and origin with ‘Pinot Meunier’, shares the rare as well as most common alleles with the presumed ‘Norton’ vinifera parent.