Fig. 1. Development of ectopic structures from roots of EMB‐9‐RAD plants of the interspecific hybrid H. annuus × H. tuberosus. A, Root bud primordia (arrow) flanking a lateral root. B, Embryogenic structures (arrows) and unorganized aggregates of callus (arrowheads) initiate on intact roots. C, Callus proliferation (arrows) at the site of lateral root initiation. D, Mass of embryogenic callus with polyembryonic structures (arrows). E, Teratological structure developed on a lateral root. F, Shoot with normal appearance (arrow). Bars = 3 mm (A and B), 2·5 mm (C and D), 2 mm (E) and 1 mm (F).