The long-running debate of whether Norton, the official state grape of Missouri, and Cynthiana, the official state grape of Arkansas, are actually the same cultivar can be put to rest.
“We employed microsatellites or simple sequence repeat (SSR) markers to construct the first genetic linkage map of Norton,” said Hwang. “Then, we conducted a genome-wide comparison with Cynthiana to find out whether these cultivars are synonymous or distinct once and for all.”
Hwang and his team obtained four samples of Norton from Missouri vineyards and three samples of Cynthiana from Arkansas vineyards. They randomly selected about 10 SSR markers from each of the 19 linkage groups in the Norton map and screened them across Norton and Cynthiana DNA samples for comparison.
The resulting banding patterns of 185 markers obtained from both cultivars showed Norton and Cynthiana are genetically identical at all selected markers.
This finding confirms with more accuracy the evidence from two past studies (1993 and 2009) that Norton and Cynthiana are the same.
Origin of the grapes
It is believed Dr. Daniel Norborne Norton grew Norton from a seed at his vineyard in Richmond, Virginia, before 1830. Cynthiana is said to come from the Arkansas woods and sent to the Prince of Flushing in New York in the 1850s.
Both gained popularity when they arrived in Hermann, Missouri – Norton in the late 1840s and Cynthiana in the late 1850s.
Impact of research
Hwang believes this study’s findings will solve the argument of which grape is which, as well as the confusion about what to call the identical cultivars.
“Our lab is scientifically validating a misnomer of the last 150 years,” said Hwang. “If the results of this study are taken into consideration, then the terms Norton and Cynthiana should be accepted as the same and used interchangeably.”
Hwang recently published an article about this research titled, “Constructing a Genetic Linkage Map of Vitis aestivalis-derived ‘Norton’ and Its Use in Comparing Norton and Cynthiana” in the Molecular Breeding journal.
The article’s co-authors include MSU graduate Mia Hammers, doctoral student Surya Sapkota and agriculture research specialist Li-Ling Chen.