Internode transverse thin-cell-layers(tTCLs) is a high efficiency shoot regeneration system with low rate of hyperhydricity.In this study,internode tTCLs of four cut spray chrysanthemum cultivars,i.e.,'Repluse','Regan Elite Improved','Regan Elite Sunny' and 'Regan Elite White',were cultured on the medium supplemented with auxin.The goal is to select the optimum concentration of auxin and the optimum location of explants for shoot regeneration.Agar concentration and culture temperature were also explored to ...