Comparative Evaluations of Commercial Seaweed Extract Formulations on Germination, Biomass Accumulation and Early Seedling Growth in Capsicum annuum

Seaweed-derived biostimulants are increasingly used to improve seed germination and early seedling development in horticultural crops. This study evaluated the effects of five commercially available seaweed extract (SWE) formulations (ASCO, AQUA, KAT, SAGA, and BIO) applied at 2 mL L−1 on germination, seedling growth, biomass accumulation, moisture-related traits, and biomass allocation indices of Capsicum annuum L. under controlled conditions. A 10-day in vitro Petri dish bioassay was conducted using five experimental replicates for each treatment. Significant differences among the treatments were observed for several germination, growth, biomass, and moisture-related parameters. KAT exhibited the highest final germination percentage, whereas SAGA exhibited the fastest germination response and the highest seedling vigor index. SAGA was associated with higher root length and total dry weight, whereas AQUA exhibited among the highest root biomass values. BIO recorded the highest moisture content, leaf length, and shoot-to-root ratio. Correlation analysis identified significant relationships among growth and biomass traits, whereas principal component analysis revealed distinct multivariate response patterns among the evaluated formulations. Overall, the commercial SWE formulations showed different response profiles during the early seedling development of C. annuum under the conditions of present study. Further studies are required to evaluate the consistency of these responses across different concentrations, cultivars, and growing environments.