The agronomic performance and yield of onion cultivars was evaluated on organic farming conditions in the Lowlands of Rio de Janeiro state, Brazil, also named Baixada Fluminense, from June to October 2010, in the municipality of Seropédica. The statistical design consisted of 10 treatments arranged in a randomized block design with four replications. We evaluated the total yield, the marketable and the unmarketable, as well as the classification of onions. The total yield of bulbs ranged from 14.42 to 24.09 t ha-1, while marketable yield ranged from 14.28 to 24.09 t ha-1. The highest yielding cultivars which can be recommended were Alfa Tropical, Alfa São Francisco, Baia Periforme, Madrugada, Primavera, Jubileu, Pêra Norte and Lola; while the lowest yielding cultivars were the Vale Ouro IPA 11 and the Franciscana IPA 10. The production of 'refused' bulbs was very low, and the cultivars Alfa Tropical, Alfa and Lola did not produce this kind of bulbs. The average weight of bulbs ranged from 54.1 to 90.3 g, and the cultivars Franciscana IPA 10 and Vale Ouro IPA 11 were those with the lowest values of 'refused' bulbs. Organic farming of onions in the studied conditions (Baixada Fluminense) is possible and capable of produce yields similar to those obtained in conventional farming.
Allium cepa; organic agriculture; agronomic characters; productivity; purple blotch
