A field experiment was carried out at Embrapa Agroforestry Research Center for the Western Amazon, in Manaus, AM, from September to December 1995, in a very clayey Yellow Latosol soil, "terra firme" ecosystem, with the objective of evaluating several summer cabbages: União, Master, Shutoku, Astrus, Saikô, Sooshu (control), Satumo, XPH 5786, XPH 5787, XPH 5904 and XPH 5909. The first six cultivars are commercial cabbages and the others expe rimental hybrids. The experiment was set out in a randomized block design with four replications and twenty plants per plot, at planting distances of 0.80 m between ridge and 0.40 m between plants. Organic and chemical fertilizers as well as indispensable cultural practices were applied. Hybrids XPH 5787, XPH 5909, XPH 5904, Satumo, Sooshu, Saikô, Astrus and Shutoku showed the highest head weight (799.03 g to 1119.54 g). Hybrids XPH 5787, XPH 5909, XPH 5904, Satumo, Sooshu, Saikô and Astrus produced highest yield (14.50 kg to 20.73 kg, per plot). Hybrids Shutoku, Astrus, Saikô, XPH 5786, XPH 5909 and XPH 5787 had the most compact heads. Hybrid XPH 5909 had the shortest core depth (C/D ratio of 0.51). The heads showed slightly lengthened shapes in hybrids Master, XPH 5786 and XPH 5787, a trait of low commercial preference. Hybrid Sooshu was the earliest with a vegetative cycle of 60 days. It was concluded that, among the commercial cultivars, the hybrids Saikô and Astrus can be tested in larger experimental areas, on "terra fir me" ecosystem, as an alternative to the control cultivar. The experi mental hybrids XPH 5909 and XPH 5787, which had good yield performances, displayed an incidence of heads with internal malformations and a later vegetative cycle than the control and the commercial hybrids Saikô and Astrus. This was the reason for not recommending these experimental cabbages.
Brassica oleracea var. capitata; cultivar; hybrid, humid tropic.