Sustainable agriculture through seaweed biostimulants: A two-year study demonstrates yield enhancement in pepper and eggplant

Nikola Staykov^1*Aakansha Kanojia¹Rafe Lyall¹Valentina Ivanova¹Saleh Alseekh^1,2Veselin Petrov^1,3Tsanko Gechev^1,4

• ¹Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria
• ²Max-Planck-Institut fur Molekulare Pflanzenphysiologie, Potsdam, Germany
• ³Agraren universitet Plovdiv, Plovdiv, Bulgaria
• ⁴Plovdivski universitet Paisij Hilendarski, Plovdiv, Bulgaria

Global climate change and unsustainable agricultural practices have intensified the need for ecofriendly strategies to improve crop resilience and productivity. This study evaluates the efficacy of a seaweed-based biostimulant derived from Ascophyllum nodosum extract (ANE) in enhancing yieldrelated traits in pepper (Capsicum annuum) and eggplant (Solanum melongena) under open-field conditions over two consecutive years. Foliar applications of ANE during early flowering stages resulted in a significant increase in total fruit yield. Yield improvements were primarily attributed to an increased number of fruits per plant and to a lesser extent to increased fruit weight/size, with hints to these effects traced back to earlier developmental stages. Metabolomic analyses revealed that ANE treatment modulated primary metabolism, enhancing sugar and amino acid levels, nitrogen assimilation, and osmoprotection, which together supported improved fruit set and development. Transcriptomic profiling demonstrated consistent gene expression changes in pathways related to to cell wall modification growth, stress response, and carbohydrate metabolism. Micronutrient Elemental analysies indicated a general nutrient dilution effect due to increased biomass, with the notable exception of magnesium, which was enriched in ANE-treated pepper fruits. These findings highlight the potential of ANE as a sustainable agricultural input to improve yield and quality in vegetable crops while supporting environmentally responsible farming practices.