Tag Archive for: seedless

Figure 1 Valley Pearl clusterM.W. Fidelibus

Valley Pearl

Valley Pearl is an early-season white-skinned table grape (Vitis vinifera L.), typically ripening in mid to late July in the San Joaquin Valley of California. This variety produces 1.3 lb conical-shaped clusters that are medium to well-filled. Berries are spherical in shape, with smooth pale green skin. Optimal berry size, 9 g, can be achieved with one application of GA3. Berries are large and sweet, with a neutral to slightly muscat flavor. Growers may expect >1,100 19-lb boxes of fruit per acre annually. Valley Pearl is patented and licensed exclusively to the California Table Grape Commission.

Figure 1 Scarlet Royal clusterM.W. Fidelibus

Scarlet Royal

Scarlet Royal is a mid-season red-skinned table grape (Vitis vinifera L.), typically ripening in mid to late August, in the San Joaquin Valley of California. This variety produces large (1.8 lb) conical-shaped clusters that are medium to well-filled (Hashim-Buckey and Ramming). Berries are oval in shape and of similar appearance to Crimson Seedless. Natural berry size is moderate to large for table grapes, 5-7 g, and generally color well naturally. Growers may expect 1,600 19-lb boxes of fruit per acre annually (Fidelibus et al., 2018). Scarlet Royal is patented and licensed exclusively to the California Table Grape Commission.

Figure 1 Autumn King clusterM.W. Fidelibus

Autumn King

Autumn King is a late-season white-skinned table grape (Vitis vinifera L.), typically ripening in late October in the San Joaquin Valley. It is notable for its very large berries (>9 g natural berry weight), and high yield potential. Head-training and cane-pruning is recommended. Preliminary reports suggested Autumn King vineyards will yield 700-800 22 lb boxes of fruit per acre each year (Hashim-Buckey and Ramming), but more recently it was suggested the variety could produce 1,800 19 lb boxes/acre annually (Fidelibus et al., 2018). The difference in yield estimates depends, in part, on berry size, as original yield estimates were based on natural berry size of approximately 10 g, but optimal cultural practices can substantially increase berry size. Autumn King is patented and licensed exclusively to the California Table Grape Commission.

Figure 2 Thompson Seedless clusterM.W. Fidelibus

Thompson Seedless

Thompson Seedless is a white seedless grape of ancient origin and suitable for a variety of uses, including table, raisin, wine, concentrate, and canning. Its leaves are also edible and used as a wrap around fillings, in types of dolma known as sarma. In California, most Thompson Seedless grapes are grown for raisins, dried on trays placed on the vineyard floor, or in dehydrators; the grapes of this variety ripen too late to dry on vine (DOV). Tray-dried raisins develop a dark brown color and are known as ‘naturals’. Some Thompson Seedless grapes are picked fresh and taken to a dehydrating facility for pretreatments, drying, and treatment with sulfur dioxide, to preserve color. Such raisins are known as “goldens,” or “golden raisins.”. Other types of raisins, including “Sultanas” and “dipped” raisins, are also made from Thompson Seedless grapes dried in a dehydrator.

Figure 2 Selma Pete clustersM.W. Fidelibus

Selma Pete

Selma Pete is a white seedless “Thompson-type” raisin grape from the USDA-ARS, selected by Ramming and Tarailo (Okie, 2002) and named after former UC Davis viticulture specialist L. Peter Christensen. Selma Pete was selected for its early maturity, ripening approximately 14 to 21 days earlier than ‘Thompson Seedless’, making it suitable for dry-on-vine (DOV) (Fidelibus, 2021; Petrucci, 2002). Selma Pete is currently the earliest-ripening Thompson-type raisin grape grown in California. It is less productive than Fiesta, but ripens sooner, dries faster, and usually produces a higher proportion of ‘B and better’ raisins (Fidelibus et al., 2008; Fidelibus, 2021). Selma Pete berries have the highest titratable acidity of Thompson-type raisin grape varieties, and the raisins are tarter as a result (Parpinello et al., 2012).

Figure 2 Solbrio clusterM.W. Fidelibus

Solbrio

Solbrio is an early-season black-skinned table grape (Vitis vinifera L.). Solbrio vines produce large berries with a crunchy texture and full color without the need for plant growth regulators. Berry taste is sweet and neutral. This variety is licensed exclusively to the California Table Grape Commission.

Figure 1 Fiesta clusterM.W. Fidelibus

Fiesta

Fiesta is a white seedless “Thompson-type” raisin grape from the USDA-ARS, selected by Weinberger and Loomis (1974). Selected for its early maturity, Fiesta ripens approximately 10 to 14 days earlier than ‘Thompson Seedless’, making it less susceptible to rain damage and more suitable for dry-on-vine (DOV) raisins (Fidelibus, 2021). Raisin varieties that ripen earlier than Fiesta have since been released, but Fiesta remains popular because it is among the most productive raisin grapes available, and ripens early enough to DOV. However, Fiesta’s large crops tend to limit soluble solids accumulation, and thus result in lower raisin quality compared to other Thompson-type DOV raisin grapes (Fidelibus et al., 2008; Fidelibus, 2021). Therefore, the need to balance acceptable soluble solids accumulation, which is critical for raisin yield and quality, against timely cane severance, which is critical to ensure adequate drying, is more difficult for Fiesta than it is for varieties such as Selma Pete or DOVine, which ripen sooner than Fiesta (Fidelibus, 2021). Fiesta is also particularly susceptible to powdery mildew, and the fruit may have fewer but larger seed traces than Thompson Seedless (Christensen et al., 1983).

Figure 2 Sunpreme cluster

Sunpreme

Sunpreme is a white seedless raisin grape bred by David Ramming, USDA-ARS. It is the first raisin variety to spontaneously dry-on-vine, without cutting canes or otherwise separating the fruit from the vine. It has fruitful basal nodes and may be spur-pruned. The combination of spontaneous drying and fruitful basal nodes should make it possible to harvest and prune Sunpreme with machines, a degree of mechanization that is not possible with other raisin varieties. However, Sunpreme is also prone to preharvest fruit drop caused by the abscission of cluster branches. Compared to other Thompson-type raisin grapes, Sunpreme has larger, rounder, berries, and heavier raisins that are lighter in color. Sunpreme grapes and raisins also have a pleasant, mild, Muscat flavor.