Seed and transplant physiology: Impact in onion establishment

Plant growth regulators (PGRs) can positively regulate seed germination and/or root growth and development. Research in onion seeds showed the PGR ethephon, to be beneficial in increasing seedling root surface area but reduced root length. Hydro-priming was shown to be a simple and viable method to enhance onion germination and root traits. A follow-up study aimed at selecting the best transplant strategies to improve onion crop performance. The impact of later planting dates and seedling densities in the trays were evaluated on growth, yield components, bulb quality and phytonutrient content of three onion cultivars (‘Caramelo’, yellow; ‘Don Victor’, yellow; and ‘Lambada,’ red). Our results demonstrated that the technique of establishing onion transplants grown from 1 or 3 seeds per cell in a tray from early November to early December provides a practical and economical alternative to achieve earlier crops while reducing the length of the production season.