Issue link: http://winesandvines.uberflip.com/i/400294
W i n e s & V i n e s n O V e M B e r 2 0 1 4 119 WineEast conducting a genome-wide comparative as- sessment using microsatellite markers in order to answer this question. Norton and Cynthiana are both described as derived from V. aestivalis. Although isozyme analy- sis in 1993 suggested that they were genet- ically identical, only five banding patterns were reported. Despite these data, Norton has been described in numerous publica- tions as distinct from Cynthiana, and grow- ers and winemakers assert that distinctions exist in their respective viticultural perfor- mance and enological quality. The authors currently are characterizing the relationship between these two cultivars using microsatellites, a simple and effi- cient procedure for genome-wide analysis. Microsatellites, or simple sequence repeats (SSrs), are one of the most popular sources of genetic markers and play a significant role in plant genetics and breeding. They present the advantage of being PCr-de- rived, co-dominant, highly polymorphic and have proved their usefulness for the genetic analysis of a heterozygous species-like grape. In concert with this study, authors constructed a genetic map of a Norton x Cabernet Sauvignon population by testing 600 SSr markers, 359 of which were infor- mative markers polymorphic for Norton in 19 chromosomes. Leaf DNA will be isolated from three accessions of Cynthiana and four accessions of Norton in Arkansas and Mis- souri. Ten randomly chosen SSr markers from each chromosome were used to com- pare the microsatellite banding patterns between Norton and Cynthiana. Canopy management Fruit-zone leaf removal has become a stan- dard cultural practice in vinifera vineyards during the past 20 years. reasons for its use are obvious: Shaded canopy fruit zones can aggravate disease management, and fruit quality can be impaired. Fruit-zone leaf and lateral shoot removal is commonly used to correct this problem. However, only general leaf-removal recommendations exist for the principally grown cultivars. Cain Hickey and Tony Wolf of Virginia Tech examined optimization of fruit-zone leaf- removal practices in Cabernet Franc and Petit Verdot. Two post-fruit-set leaf/lateral- removal treatments (medium, high re- moval)—one pre-bloom leaf/lateral removal treatment (PB) and a no-leaf removal con- trol—were compared to determine their im- pacts on cluster compactness, components of yield and fruit composition in Cabernet Franc and Petit Verdot. They hypothesized that PB removal would loosen clusters, re- duce yields and improve fruit composition in both cultivars. Compared to the control, PB removal loosened Cabernet Franc clusters by 16% and Petit Verdot clusters by 10%. PB re- moval reduced crop yield by 46% and berry weight by 6%. Medium reduced yield by 26% and berry weight by 4% in Cabernet Norton has been described as distinct from Cynthiana, and growers and winemakers assert that distinctions exist. Exp. Dec. 31, 2014