A study was carried out at the Monte Alegre do Sul Experiment Station, State of São Paulo, Brazil (22°42'S), to evaluate five short day marketable onion (Album cepa L.) hybrids (Granex 33, Granex 429, Baia Ouro AG-55, Baia Ouro AG-55R and Baia Ouro AG-59) and five short day experimental onion hybrids (FMX-151, FMX-179, FMX-181, FMX-182 and FMX-183) from different origins. The sowing date was March 21, 1983 and the harvest period occurred from September 21 to November 7. The hybrids Granex 33, Baia Ouro AG-55 and Baia Ouro AG-59 yielded more than the hybrids FMX-181 and FMX-182. However, their yields were not statistically different from those of the following hybrids: Baia Ouro AG-55R, Granex 429, FMX-151, FMX-179 and FMX-183. In relation to the average weight of marketable bulbs, Baia Ouro AG-55 and Baia Ouro AG-59, were statistically superior to Baia Ouro AG-55R, Granex 429, FMX-181, and FMX-182. Considering type and shape of bulbs, Baia Ouro AG-55R, FMX-181, FMX-182 and FMX-183 showed higher porcentages of "charuto" type of bulbs than the others, while FMX-181, FMX-182 and FMX-183 presented also higher desuniformity in bulb shapes. The occurrence of "bolting" was not observed. In relation to the vegetative cycle, Granex 33 was the earliest while Baia Ouro AG-55 was the latest. The onion hybrids Granex 33, Granex 429, Baia Ouro AG-55, Baia Ouro AG-59, FMX-151 and FMX-179 were recommended to the growers of Monte Alegre do Sul, and areas of similar climatic conditions.
onion (Allium cepa L.); hybrids; behavior