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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 #413274

Research Project: Water and Nutrient Management for Sustainable Production of Small Fruit and Nursery Crops

Location: Horticultural Crops Production and Genetic Improvement Research Unit

Title: Biostimulants with glycine betaine or kelp extract alleviate heat stress in red raspberry (Rubus idaeus)

Author
item MAKONYA, G. MUNASHE - Washington State University
item Bryla, David
item Hardigan, Michael
item HOASHI-ERHARDT, WENDY - Washington State University
item DEVETTER, LISA - Washington State University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2024
Publication Date: 1/17/2025
Citation: Makonya, G.M., Bryla, D.R., Hardigan, M.A., Hoashi-Erhardt, W., DeVetter, L.W. 2025. Biostimulants with glycine betaine or kelp extract alleviate heat stress in red raspberry (Rubus idaeus). Scientific Reports. 15:2251. https://doi.org/10.1038/s41598-024-83955-7.
DOI: https://doi.org/10.1038/s41598-024-83955-7

Interpretive Summary: The Pacific Northwest region of the United States, which includes the states of Washington and Oregon, is an important area for production of raspberries, supplying both domestic and international markets. In recent years, extreme heat events have become more frequent and severe in the region, leading to reduced production, and causing economic hardships among many growers. In collaboration with researchers at Washington State University, ARS scientists in Corvallis, Oregon, evaluated whether biostimulants, a class of natural or synthetic substances that can be applied to plants to improve their tolerance to extreme temperatures, could be used to protect young raspberry plants from heat damage. Two products, including one containing glycine betaine (an amino acid derivative) and another containing kelp extract, improved growth, photosynthesis, and antioxidants in the leaves of plants exposed for four weeks to daily highs of 95 to 113 degrees Fahrenheit. Commercial fields threatened by high temperatures could benefit from application of products containing these active ingredients.

Technical Abstract: Heat stress disrupts plant physiological processes and reduces global food crop production. Biostimulants are an emerging and innovative class of agricultural products that may mitigate the adverse effects of heat, but research on their efficacy in horticultural crops is lacking. The objective of this study was to evaluate the ability of several commercially available biostimulants to alleviate heat stress in red raspberry. Three biostimulants, including FRUIT ARMOR, Optysil, and KelpXpress [active ingredients glycine betaine, silicone, and kelp (Ascophyllum nodosum) extract, respectively] were applied weekly for 28 days to the soil and leaves of three floricane-fruiting raspberry genotypes (‘Meeker’, WSU 2188, and ORUS 4715-2) exposed to high temperatures (> 35 C/day) inside a glasshouse. ‘Meeker’ consistently maintained high chlorophyll fluorescence (Fv/Fm) and photosynthesis under control and biostimulant treatments. However, Fv/Fm and photosynthetic performance of WSU 2188 and ORUS 4715-2 increased when treated with FRUIT ARMOR. Application of KelpXpress also improved the Fv/Fm and photosynthetic performance of WSU 2188. Consistent with other physiological results, ‘Meeker’ and WSU 2188 plants treated with FRUIT ARMOR and KelpXpress accumulated more anthocyanins and exhibited greater shoot and total biomass than ORUS 4715-2. Results from the study demonstrate genotype and commercial biostimulants vary in their response and ability to mitigate heat stress over time. The superior physiological performance of ‘Meeker’ under control and biostimulant treatments manifested in improved heat tolerance. The improved physiological and biochemical performance of WSU 2188 and ORUS 4715-2 suggests that some of the biostimulants under investigation contribute towards enhanced repair and maintenance of photosystem II structural integrity, as well as improved photosynthetic performance and antioxidative capabilities. The contribution of the biostimulants towards improved physiological, biochemical, and growth performance supports their potential role in enhancing thermotolerance of raspberry and other horticultural crops exposed to heat stress.