‘Thunderhead’ erect primocane fruiting blackberry

Authors: Hardigan, Michael; Finn, Chad; JONES, PATRICK - Oregon State University; STRIK, BERNADINE - Oregon State University; Peterson, Mary; Bassil, Nahla; King, Ryan; WIEGAND, ZACHARY - Oregon State University; OLAYA, CRISTIAN - Oregon State University; Martin, Robert; Lee, Jungmin; LUKAS, SCOTT - Oregon State University

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/14/2025
Publication Date: 8/1/2025
Citation: Hardigan, M.A., Finn, C.E., Jones, P.A., Strik, B.C., Peterson, M.E., Bassil, N.V., King, R., Wiegand, Z.J., Olaya, C., Martin, R.R., Lee, J., Lukas, S.B. 2025. ‘Thunderhead’ erect primocane fruiting blackberry. HortScience. 60(8):1366–1371. https://doi.org/10.21273/HORTSCI18617-25.
DOI: https://doi.org/10.21273/HORTSCI18617-25

Interpretive Summary: Primocane fruiting blackberry cultivars remain relatively new in plant breeding, with commercial cultivars having emerged only in the last two decades. They have rapidly increased their importance for the US and global fresh market blackberry industry. Specifically, erect primocane fruiting blackberry cultivars reduce inputs and management costs for growers related to pruning, training, and overwintering that make traditional floricane blackberry cultivars highly labor intensive. Furthermore, their primocane flowering and ripening habit (also known as everbearing) allows for greater flexibility in terms of what season a crop can be produced in, and allows for more consistent production in low-chill regions. Key challenges for primocane fruiters are residual genetic spininess, a narrow gene pool due to a population bottleneck caused by introgression of the PF allele, and yields and fruit quality generally below the best commercial floricane fruiting types. We have addressed several of these issues with the development and release of primocane fruiting blackberry cultivar ‘Thunderhead’, which possesses exceptional yields and fruit quality for a primocane type of blackberry, excellent plant health and vigor, and reduced spininess. ‘Thunderhead’ rivals the yields of productive floricane fruiters with the primocane fruiting habit, and will make growers more profitable by combining high yields and fruit quality with reduced production costs.

Technical Abstract: ‘Thunderhead’ is an erect, primocane fruiting blackberry (Rubus subg. Rubus Watson) with high yields of berries with excellent firmness and fruit quality for the fresh market. ‘Thunderhead’ is the first erect primocane fruiting blackberry released by the USDA-ARS in Oregon. The cultivar contains a genetic background derived primarily from eastern U.S. primocane fruiting blackberry germplasm developed previously by John Clark at the University of Arkansas. ‘Thunderhead’ can be distinguished by its exceptionally high plant vigor and yields of medium-to-large sized berries with excellent firmness, fruit quality, flavor, and relatively small seed size for an erect primocane type. The cultivar compensates for a lack of complete genetic spinelessness with outstanding plant vigor and fruiting performance. ‘Thunderhead’ berries are well-suited for fresh consumption, with good sweetness and gloss when picked firm, and low bitter notes. ‘Thunderhead’ begins ripening in Oregon during the late summer at a similar time to ‘Prime-Ark® 45’ but produces greater yields with comparable firmness and skin toughness and lower red drupelet reversion. ‘Thunderhead’ is expected to be adapted to areas where other erect and semi-erect floricane or erect primocane blackberries can be grown successfully. A U.S. Plant Patent was granted in 2023 (US PP34,914 P2).