**5. Conclusions**

In summary, all the three plant growth hormones of IAA, IBA and ABT-1, were able to promote the rooting of cuttings of vegetable mulberry and fruit mulberry, with ABT-1 exhibiting the best effect. Among them, the treatment with 1000 mg·L−<sup>1</sup> ABT-1 presented the optimal impact on the rooting of vegetable mulberry, with a rooting rate of 63.3% and a rooting effect index of 25.3. The treatment with 500 mg·L−<sup>1</sup> ABT-1 showed the optimal impact on the rooting of fruit mulberry, with a rooting rate of 68.7% and a rooting effect index of 34.3. During the rooting process, ABT-1 treatment effectively increased the contents of IAA, IBA, JA and SL, and decreased the contents of ABA, ZR, and GA3, contributing to the production of adventitious roots. The rooting mechanism of plant cuttings is extremely complex, and follow-up studies will focus on molecular biology methods including transcriptomics and proteomics [60], thereby further revealing the rooting mechanism of vegetable mulberry and fruit mulberry cuttings.

**Author Contributions:** Conceptualization, J.Q. and H.B.; methodology, J.Q. and H.C.; software, H.C. and Y.L.; validation, Y.L., J.S., M.M. and P.D.; Data Curation, H.C., J.S., M.M. and P.D.; writing original draft preparation, H.C. and Y.L.; writing—review and editing, J.Q. and H.B.; funding acquisition, J.Q. and H.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China (grant number 31700549) and Forestry Germplasm Resources Project of Henan Province (grant number 30802649).

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.
