Consideration of adenine hemi-sulfate effect on increasing the direct regeneration rate of carnation cultivars’ leaf explants

The genetic improvement of carnation (Dianthus Caryophyllus), as one of the most important cut flowers in the world, is of utmost significance. For this purpose, the use of in vitro breeding techniques is very important. One of the most crucial in vitro breeding needs of carnation is accessibility to a regeneration method with maximum productivity and minimum genetic modification probability. The present study aimed to determine an optimal and fast method for the direct regeneration of carnation cultivars by employing various regulators and adenine hemi-sulfate for the first time in these cultivars.

For the determination of the optimal level of the culture medium compositions toward the direct regeneration of carnation cultivars (Skimo, Tibor, and Labret), an experiment with a completely randomized design was designed and implemented in an MS culture medium, in different concentrations of growth regulators, including four levels of TDZ (0.5, 1, 2, and 3mg/L), two levels of IAA (0.5 and 1mg/L), and four levels of adenine hemi-sulfate (0. 20, 40, and 80mg/l), were used.

The model used for this experiment was significant at the level of 1%, where R2=96% and CV=22, indicating the acceptable accuracy of the analysis. With respect to the results, it was observed that, in the leaf explants of different carnation cultivars, the utilization of the MS culture medium in light conditions with TDZ 2 mg/L+ IAA 0.5 mg/L occurred the direct regeneration of the leaf explants. It is worth mentioning that the addition of 40mg/L of adenine hemi-sulfate to the culture medium increased the regeneration mean from 66% to 94% among different cultivars. In addition, the mean shoot number per explant increased from 12 to 36 shoots.

Generally, the results of the experiments showed that the mixing of the MS base medium, leaf explants in light conditions, and the TDZ 2 mg/L+ IAA 0.5 mg/L+As 40 mg/L regulator composition significantly led to the leaf regeneration of carnation cultivars. Briefly, the results of this study proved that the use of adenine hemi-sulfate significantly impacted the upsurge of the direct regeneration rate of carnation cultivars.