Department of Plant Sciences

The hollow stem disorder (HSD) is a common problem in cauliflower caused by B deficiency. Its occurrence is related especially to nitrogen and boron supply. There is only little information about this subject in Brazil. Two experiments were carried out in a randomized complete block design with 4 replications from November 2005 through February 2006. The objective was evaluate rates of nitrogen (100, 150, 200, 250 kg ha-1) and B aplication (0 at planting; 1.5 kg ha-1 planting + 1.5 kg ha-1 at curd initiation; 3 kg ha-1 at planting) on production and HSD incidence in cauliflower “Sharon” cultivated on Kandiustalf (PVA; 0.54 mg kg-1 B) and Rhodic Kandiudox (NVef; 0.84 mg kg-1 B) soils. The curd diameter and total yield were neither influenced by N nor B application in spite of generally low N concentrations in leaves and curds. On NVef soil HSD occurred without affecting commercial yield even with B concentrations in leaves and curds suggesting adequate B status. On PVA soil B application increased commercial yield by reducing the incidence of HSD. There was negative correlation between B concentration in leaves (r=0.66; p < 0.05) and curds (r=0.76; p < 0.05) with hollow stem disorder. Further studies appear necessary to control this B deficiency induced physiological disorder prevailing under tropical conditions.