Fig. 2 Selection and regeneration of transgenic wheat. A, Calli on selective medium containing 0.0375 g L^-1 of cyanamide 8 wk following bombardment. B, Shoot formation from cyanamide-resistant callus tissue. C, A series of dilutions for the colorimetric assay (left to right); 0, 40, 20, 10, 5, 2, and 1 mM of cyanamide. D, Use of the colorimetric assay to test for the presence of cyanamide hydratase (left to right); nonplant sample containing no cyanamide (cuvette no. 1), nonplant sample containing 5 mM cyanamide (cuvette no. 2), transformed plant sample containing 5 mM cyanamide (cuvette no. 3), and a nontransformed plant sample containing 5 mM cyanamide (cuvette no. 4). E, Wheat plantlets sprayed with a Dormex solution (10%) 2 wk after planting; sprayed nontransformed control plant (right), sprayed 1722 plant (left). F, Wheat plants growing in the presence (3 g) of Perlka 2 wk after application, control wheat plant (left) and a plant of the 1722 line (right)