Abstract: In order to choose the suitable target source and developmental stage of wheat explants for establishment of high frequency of plant regeneration system,inflorescence and scutellum explants were cultured in vitro conditions to study the effects of the explants physiological state on the frequencies of callus induction and plant regeneration.Three size classes of inflorescence(1.3～2.0 cm,0.8～1.2 cm,0.4～0.7 cm in length) and immature embryo scutellum(1.2～1.5 mm,0.8～1.1 mm,0.4～0.7 mm in diameter) were used in this study from two winter wheat genotypes En1 and E55072.According to statistical analysis,the results indicated that the explants showed significantly differences in terms of callus induction and plant regeneration in in vitro culture from explants with different size classes.For inflorescence,explants with 0.5～ 1.0 cm in length give better response,from which per embryogenic callus produced 3.17 plantlets.For scutellum,explants with 0.4～1.1 mm in diameter gave better response,from which per embryogenic callus generated 5.63 plantlets.