Maximizing growth and productivity of onion (Allium cepaL.) bySpirulina platensisextract and nitrogen-fixing endophytePseudomonas stutzeri

The study focuses on the impact of foliar spraying cyanobacteriumSpirulina platensisextract and the inoculation with the endophyte N-2-fixingPseudomonas stutzeri, and their mixture in the presence of different nitrogen doses on growth and yield of onion under field conditions. Bioactive compounds ofSpirulinaandPseudomonaswere analyzed by GC-MC and amino acid production ofSpirulinaby the amino acid analyzer. Hydrogen cyanide (HCN), indole acetic acid (IAA), ammonia (NH3), pectinase activity, and N-2-fixation ofPseudomonaswere measured. Plant height (cm), leaf length (cm), number of green leaves, bulb diameter (cm), fresh and dry weight of plant (g), chlorophyll a, b of leaves, bulb weight (g), marketable bulb yield (t. ha(-1)), cull bulb weight (t. ha(-1)), total bulb yield (t. ha(-1)), bulb diameter (cm), total soluble solids (TSS%), dry matter content (DM%), evaluation of storage behavior, and economic feasibility were estimated.Spirulinaextract has several bioactive compounds.Pseudomonascan produce HCN, NH3, IAA, pectinase, and nitrogen fixation. The application of mixture with recommended dose of nitrogen increases the onion plant parameters, marketable yield, total bulb yield, bulb weight, bulb diameter, TSS%, DM%, net return, benefit-cost ratio (B:C), lowest cumulative weight loss% of bulbs during storage, and reduce culls weight compared with other treatments in two seasons. Application ofS. platensisextract and inoculation with endophyte nitrogen-fixingP.stutzerienhance the growth and productivity of the onion under different doses of nitrogen fertilizer.

Automated summary

The study investigated the impact of Spirulina extract and nitrogen-fixing endophyte on the growth and yield of onion plants under different nitrogen doses. Results showed that the mixture of Spirulina and Pseudomonas had a significant positive effect on plant parameters, marketable yield, bulb weight, and other factors when applied with recommended nitrogen dose. Spirulina extract is rich in bioactive compounds, while Pseudomonas can produce various beneficial substances to enhance onion growth and productivity.