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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Production and Genetic Improvement Research Unit » Research » Publications at this Location » Publication #433174
Research Project: Sustainable, Climate-Smart Solutions for Profitable Production of Small Fruit and Nursery Crops

Location: Horticultural Crops Production and Genetic Improvement Research Unit

Title: Genotypic variation in physiological and yield responses to heat stress mitigation strategies during raspberry establishment

Author
item MAKONYA, G. MUNASHE - Washington State University
item Bryla, David
item HOHEISEL, GWEN - Washington State University
item PETERS, R. TROY - Washington State University
item YOUSSEF, MOHAMED - Washington State University
item Hardigan, Michael
item HOASHI-ERHARDT, WENDY - Washington State University
item DEVETTER, LISA - Washington State University

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2026
Publication Date: 4/16/2026
Citation: Makonya, G., Bryla, D.R., Hoheisel, G.A., Peters, R., Youssef, M.A., Hardigan, M.A., Hoashi-Erhardt, W., DeVetter, L.W. 2026. Genotypic variation in physiological and yield responses to heat stress mitigation strategies during raspberry establishment. HortScience. 61(5):1043-1052. https://doi.org/10.21273/HORTSCI19350-26.
DOI: https://doi.org/10.21273/HORTSCI19350-26

Interpretive Summary: Extreme heat poses a growing threat to the productivity of many high-value horticultural crops, including red raspberries. In a collaborative effort with Washington State University, ARS scientists in Corvallis, OR, demonstrated that both overhead cooling and shade cloth effectively mitigate these negative impacts, particularly in semi-arid climates. These strategies consistently improved canopy microclimate, enhancing key physiological processes like photosynthesis and water relations. Ultimately, this led to increased fruit yield across various genotypes, highlighting the practical benefits of these interventions. The research thus underscores that optimal raspberry production under heat stress necessitates a combined approach, integrating heat-tolerant cultivars with appropriate environmental management strategies, while accounting for plant maturity and seasonal conditions.

Technical Abstract: Extreme heat increasingly threatens the productivity of high-value horticultural crops, including red raspberry (Rubus idaeus). This study evaluated the effectiveness of two heat mitigation strategies, overhead cooling and shade cloth, relative to an untreated control, on the physiological performance of four floricane-fruiting raspberry genotypes (‘Meeker’, ‘WakeField’, ‘Cascade Legacy’, and ORUS 4715-2) grown in a semi-arid climate with hot, dry summers during the 2023 and 2024 cropping seasons. Shade cloth and overhead cooling consistently improved canopy microclimate conditions, preserving photosystem II efficiency (Fv/Fm), net CO2 assimilation (A), transpiration (E), and stem water potential (SWP) relative to the untreated control. In the establishment year, shade cloth improved A and E compared to overheat cooling and untreated controls, suggesting that moderated radiation and temperature supported photosynthetic acclimation. By the second year, as plants matured and produced their first crop, both overhead cooling and shade cloth enhanced gas exchange and water relations across genotypes. Fruit yield was also higher under both heat mitigation strategies compared to the untreated control. Genotypic differences were also evident, with ‘Meeker’ and ‘WakeField’ maintaining higher photosystem II efficiency and fruit yields compared with ‘Cascade Legacy’, while ORUS 4715-2 was intermediate. These results underscore that optimal raspberry production under heat stress requires aligning heat-tolerant cultivars with appropriate environmental management strategies, with effectiveness varying by plant maturity and seasonal conditions.