Broccoli (Brassica oleracea var. italica) cultivar, Commander, characterized by low susceptibility to the hollow stem disorder commonly associated with boron (B) deficiency was compared to one with high susceptibility (cv. Stolto) and to two which are grown commercially (cvs. Baccus and Premium Crop). Beginning 3 wk after germination plants grown in a glasshouse in vermiculite were supplied continuously with a nutrient solution containing adequate B (0.5 mg L−1) or none (deficient), or were supplied initially with 0.5 mg B L−1 up to the initiation of inflorescence development after which no B was supplied. All cultivars showed visible symptoms of B deficiency (leaf midrib cracking, stem corkiness, necrotic lesions and hollowing in the stem pith) and reductions in shoot fresh weight with the zero B treatment, but Commander was least affected. Also, the B concentrations of the florets from Commander were highest and showed the lowest percent decline relative to the 0.5 mg B L−1 treatment. When B was removed from the nutrient solution at initiation of inflorescence development, the B concentrations of the florets and young leaves of all cultivars were higher than in the zero B treatment. Compared to the 0.5 mg B L−1 treatment, the B concentrations of old leaves from all cultivars were reduced, but only in Premium Crop was the floret B significantly decreased.Key words: Boron nutrition, Brassica, broccoli, nutrient deficiency, retranslocation