One objective was to study the production of onion Allium cepa L.. bulb sets in a protected environment in a seedling system with trays with different number of cells: 288 (1 plant/cell), 128 (3 to 5 plants/cell) or 72 cells (5 to 9 plants/cell) using the cultivar Serrana. The second purpose was to compare nine cultivars, grown in trays of 128 cells, with 3 plants per cell. In the first experiment, five replications were used in the trial of types of trays and densities, while four replications were used in the experiment concerning cultivars which was set out in a randomized block design. Each plot was represented by one tray. It was observed that at the higher the plant density, there was a smaller bulb set size (diameter and weight). With good fertilizer management it was possible to produce bulb sets with a diameter of 1.3 cm (2g) in a tray of 128 cells and 5 plants/cell. Among the nine cultivars examined, Crioula - AF, Crioula - GL and Houston had 83%, 67% and 81% bulb formation, respectively. The other cultivars (Aurora, Baia Periforme, Brownsville, Petroline, Pira Ouro, Pirana and Serrana) produced no thick stems. The main advantages of producing bulb sets in this system over the traditional system were: relatively higher uniformity and absence of weeds or pathogens. This system may be a good alternative for producing bulb sets for processing, for controlling seed quality and for use in the onion breeding programs.
Allium cepa; bulb sets; tray
