2026/04/16 by Givemore Munashe Makonya, David R. Bryla, Gwen Hoheisel +5 · 1 voice
Agricultural and Biological Sciences · Environmental Science · #Berry genetics and cultivation research #Turfgrass Adaptation and Management #Plant Physiology and Cultivation Studies
paper · doi:10.21273/hortsci19350-26
openalex publication_date 2026/04/16 · openalex created_date 2026/04/17 · openalex updated_date 2026/07/22
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 shadecloth, 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 semiarid climate with hot, dry summers during the 2023 and 2024 cropping seasons. A split-plot randomized complete block design tested heat mitigation treatments as main plots and genotypes as split plots with four replications. Shadecloth and overhead cooling consistently improved canopy microclimate conditions, preserving photosystem II efficiency ( F v / F m ), net CO 2 assimilation ( A ), transpiration ( E ), and stem water potential relative to the untreated control. In the establishment year, shadecloth improved A and E compared with 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 shadecloth enhanced gas exchange and water relations across genotypes. Fruit yield was also higher under both heat mitigation strategies compared with the untreated control. Fruit yield was positively associated with net photosynthesis, transpiration rate, and F v / F m across genotypes and heat mitigation treatments. 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.