Raul Cauduro Girardello, Anita Oberholster,* Andrew Walker, S. Kaan Kurtural, and Danielle Zaccaria
*University of California, Davis, 1 Shields Ave, Davis, CA 95616 (aoberholster@ucdavis.edu)

Grapevine cultivars have several clones that may vary for specific viticultural and enological characteristics such as yield, cluster and berry size, and berry composition. Vitis vinifera cv. Petite Sirah, also known as Durif, has become an important component of red wines in California. However, little is known regarding the viticultural and enological traits of Petite Sirah clones. This study evaluated phenotypic and enological traits of four clones of V. vinifera L. cv Petite Sirah grapevines. This study was performed in 2019 and 2020 at the University of California, Davis, where four Petite Sirah clones (Durif FPS1, FPS3, FPS4, and FPS5) were planted in 2010 in a complete block design. For each clone, four biological repetitions composed of five grapevines were evaluated for viticultural attributes such as number of clusters/vine, cluster weight, cluster morphology, number of berries/cluster, berry weight, pruning weight, and yield. Grape berries were collected at harvest and analyzed for basic chemical composition (Brix, pH, titratable acidity [TA]), phenolic profile by RP-HPLC and protein precipitation assay, and volatile composition by HS-SPME-GC-MS. Wines were made from each clone and analyzed for chemical and phenolic composition and aroma volatile profiles, while wine sensory attributes were evaluated by descriptive analysis. No major differences were observed in phenotypic traits such as cluster weight and berries/cluster among the clones. However, yield, pruning weight, berry weight, Ravaz index, and berry chemical and phenolic composition were demonstrated to be distinct among the clones. For instance, clones FPS 3 and FPS 5 had significantly more anthocyanin, flavanol, and hydroxycinnamic acid concentrations than FPS 1 and FPS 4. Clonal wines also exhibited unique volatile profiles that correlated well with the sensory differences among the wines.

Funding Support: Bogle Vineyards