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).
Origins and History
Fiesta was the result of a complex cross of other V. vinifera varieties, selected by Weinberger and Loomis, and released by the USDA-ARS in 1973.
Fiesta is suitable for head or cordon training (Fidelibus et al., 2008), but basal buds have low fertility, so it must be cane-pruned (Cathline et al., 2020). Fiesta is a moderate to vigorous variety with a tendency to produce narrow-diameter primary fruiting canes with strong lateral shoots (Christensen, 2000). Thus, lateral shoots may be stronger and more well-developed than the primary fruiting canes, in which case laterals may be selected as fruiting canes (Christensen, 2000a).
Clusters are large (average 1 lb), conical to shouldered, with medium (2 g), oval-shaped berries (Figure 1). Berries have thin, tender, skin, with small to medium sized seed traces. Seed traces are more pronounced on young own-rooted vines compared to older or grafted vines (Christensen et al., 1983). Fiesta typically ripens in mid-late August in the San Joaquin Valley and tends to have slightly lower titratable acidity than Thompson Seedless at the same level of soluble solids (Fidelibus et al., 2008; Fidelibus, 2021). Fiesta grapes dry more rapidly than Thompson Seedless, even when both are harvested on the same date and at the same maturity (Christensen, 2000a). This is helpful for DOV, but it makes Fiesta grapes more prone to caramelizing when dried on trays (Christensen, 2000a). Vines are sensitive to GA3, so it should not be used. Fiesta is highly susceptible to powdery mildew, Phomopsis cane and leaf spot, and Pierce’s disease. It is also more prone to bunch rot.
Fiesta was originally selected as an early-ripening variety for tray drying. Earlyness is advantageous in avoiding rain damage, but earlier drying may expose the fruit to hotter temperatures, which could increase the risk for caramelization, especially for Fiesta, which has thinner berry skin than Thompson Seedless. Trellis and vineyard design considerations for tray-drying have been described in the Raisin Production Manual (Christensen, 2000b).Most new Fiesta vineyards are designed for DOV, with either open-gable (Fidelibus et al., 2008) or overhead arbor trellises (Fidelibus, 2021). Vines on either type of trellis can be head-trained or cordon-trained, and cane pruned. It may be easier to maintain spur positions on head-trained versus cordon-trained vines, but cordon training could facilitate canopy management and pruning. Fruit on an open-gable trellis may dry better than they do on an overhead arbor, as canopy management practices, such as hedging, can allow for better sun exposure. However, vines on an overhead arbor have a higher yield potential. Cost and return studies for DOV raisin grapes on open gable and overhead arbor trellises are available (Fidelibus et al. 2016a; Fidelibus et al., 2016b).
Fiesta generally has among the lowest raisin grades of Thompson-type raisin grapes in California, at least partly due to its tendency to produce heavy crops, which limit timely accumulation of soluble solids. Low raisin grades appear to be a consequence of crop load, as vines with low crop loads had high raisin grades (Parpinello et al., 2012). Dry-on-vine raisins from Fiesta also tend to have relatively high moisture content at harvest, due to the tendency of growers to initiate cane severance later, at lower soluble solids, than they would with earlier-ripening varieties. Fiesta raisins may also have larger seed traces than other Thompson-type raisin varieties, and Petrucci (2000) noted that Fiesta raisins tend to retain a tiny fragment of the “capstem” referred to as a “nub.”
Weinberger, J.H., and N.H. Lewis. 1974. ‘Fiesta’ grape. HortScience 9:603.
Petrucci, V.E. 2000. Raisin grape varieties, p. 67. In: V.E. Petrucci and C.D. Clary (eds.). A treatise on raisin production, processing, and marketing. Malcolm Media Press, Clovis, CA.
Fidelibus, M.W., L.P. Christensen, D.G. Katayama, and D.W. Ramming. 2008. Early-ripening grapevine cultivars for dry-on-vine raisins on an open-gable trellis. HortTechnology 18:740-745.
Parpinello, G.P., H. Heymann, S. Vasquez, K.A. Cathline, and M.W. Fidelibus. 2012. Grape maturity, yield, quality, sensory properties, and consumer acceptance of Fiesta and Selma Pete dry-on-vine raisins. American Journal of Enology and Viticulture 63:212-219.
Fidelibus, M.W. 2014. Grapevine cultivars, trellis systems, and mechanization of the California raisin industry. HortTechnology 24(3):285-289.
Fidelibus, M.W. 2021. Grapevine variety and number of canes affect dry-on-vine (DOV) raisin production on an overhead arbor trellis. Horticulturae 2021, 7(10), 356; DOI:10.3390/horticulturae7100356
Cathline, K.A., G. Zhuang, and M.W. Fidelibus. 2020. Productivity and fruit composition of dry-on-vine raisin grapes pruned to 15- or 20-node canes on an overhead trellis. Catalyst: Discovery into Practice. DOI:10.5344/catalyst.2020.20002
Christensen, L.P. 2000a. Raisin grape varieties, p. 43-44. In: L.P. Christensen (ed.). Raisin production manual. University of California Agricultural and Natural Resources, Oakland.
Christensen, L.P. 2000b. Standard trellising, p. 82-86. In: L.P. Christensen (ed.). Raisin production manual. University of California Agricultural and Natural Resources, Oakland.
Fidelibus, M.W., A. Ferry, L. Jordan, G. Zhuang, D.A. Sumner, and D. Stewart. 2016a. Sample costs to establish a vineyard and produce dry-on-vine raisins - open gable trellis system. University of California Cooperative Extension, Department of Agricultural Resource Economics, Davis.
Fidelibus, M.W., A. Ferry, L. Jordan, G. Zhuang, D.A. Sumner, and D. Stewart. 2016a. Sample costs to establish a vineyard and produce dry-on-vine raisins – overhead trellis system. University of California Cooperative Extension, Department of Agricultural Resource Economics, Davis.
Christensen, L.P., D. Ramming, and H. Andriss. 1983. Seed trace content of Fiesta grapes. American Journal of Enology and Viticulture 34:257-259.