Influence of Commercial Seaweed Extract and Microbial Biostimulant on Growth, Yield, Phytochemical Content, and Nutritional Quality of Five <i>Abelmoschus esculentus</i> Genotypes

Biostimulant application during the cultivation of underutilized crops is an environmental-friendly approach for their production and utilization to promote food security and human health. This study investigated the effect of two commercial biostimulants (a seaweed-based extract, Kelpak^® (1:100, 1:40, and 1:20, dilutions), and plant growth promoting rhizobacteria, PGPR (1:5, 1:10, and 1:15, dilutions)) on the growth, yield, phytochemical content, and nutritional quality of five selected <i>Abelmoschus esculentus</i> genotypes. Biostimulant application significantly influenced vegetative growth and yield in a dose-dependent manner. Plant height, chlorophyll content, stem diameter, number of pods, and total pod fresh and dry weights increased with a decrease in dilution of the biostimulants. The application of PGPR (1:5) significantly promoted both the vegetative growth (plant height, chlorophyll content, and stem diameter) and yield (number of pods, total fresh weight, and total dry weight) when compared to the control (untreated plants) and other biostimulant dilutions. Genotype and biostimulant application had an interactive effect on all the phytochemical (total phenolics, flavonoids, and condensed tannins) and nutritional (β-carotene, vitamin C, calcium, iron, potassium, magnesium, sodium, and zinc) qualities evaluated. This study demonstrated the differential effect of biostimulant application on <i>A</i>. <i>esculentus</i> genotypes. These biostimulants can be used to enhance growth, yield, biochemical, and nutritional contents of underutilised crops such as <i>A. esculentus</i>, depending on the crop genotype, in order to improve crop productivity and combat food insecurity especially in food insecure communities.