The regeneration of whole fertile sunflower plants is highly variable and depends mainly on the genotype, though the nature of the explant and the hormone content of the culture medium are also important. Ten Helirtnthus annuus L. genotypes were evaluated ur uitro for their morphogenic response: the inbred lines HA 3004, HA 89A, cp 762A, Gp 7628, RHA 274, Rf BS-SO, and the hybrids HpS-4, Morgan 733, ACA 984, and Contiflor 3. Cotyledons of mature seeds were used as explants. The basa-l medium was MS, to which different concentrations of growth regulators were added: Mr, KIN 2 mg/l + IAA 1 mg,rl i MII, BA0.5 mg/t + IAA0.5 mg/t: MIII, MI + O.I mgll cAg; and MM MII + 0.1 mg/l GA3. All media contained 200 mgll of glutamine. Callus (C), regeneration (R), and hypertrophy (H) percentages were evaluated on the 30th day after initiation of the culture. The statistical analysis showed significant differences among genot5æes and non-significant differences. "-orig media for R. Lack of independence for genotype-regeneration was also detected by the G-test.