Purpose To identify the rooting physiological differences of six highly cold- and drought-resistant peach varieties (Jiuyuhongguang No. 1, Jiuyuhongguang No. 5, Jiuxiang No. 1, Jiuxiang No. 2, Daqingpi, and Ziyantao) under indole-3-butyric acid (IBA) treatment, and to screen suitable varieties for cutting propagation.
Methods Using water as a control (CK) and 200 mg/L IBA as the treatment, the dynamic changes in endogenous hormones auxin (indole-3-acetic acid, IAA), cytokinin (CTK), antioxidant enzymes indoleacetic acid oxidase (IAAO), peroxidase (POD), oxidative damage (malondialdehyde content), and nutrients (soluble sugar, total nitrogen, total phosphorus, total potassium) at the base of cuttings from 7 to 35 days during the rooting process were measured.
Results IBA could improve rooting rate obviously, with Ziyantao and Jiuxiang No. 2 showing the highest rates of 78.00% and 71.00%, respectively. Under IBA treatment, Ziyantao and Jiuxiang No. 2 exhibited higher IAA/CTK ratios on the 21st day of cuttings, whereas Jiuxiang No. 1 and Jiuyuhongguang No. 1 reached maximum values on the 35th day of cuttings. Under IBA treatment, Ziyantao exhibited the lowest IAAO activity and malondialdehyde content, and the highest total potassium content on the 21st day of cuttings, which promoted root formation; at the same time, Jiuxiang No. 1 showed the highest IAAO activity and the lowest total potassium content, thereby inhibiting its rooting. An extremely significant positive correlation was found between IAA and CTK in the high-rooting-rate varieties, Ziyantao and Jiuxiang No. 2 (P<0.01); in the low-rooting-rate variety Jiuxiang No. 1, an extremely significant positive correlation was observed between POD and malondialdehyde (P<0.01).
Conclusion Exogenous IBA promotes peach rooting by optimizing the hormonal-antioxidant-nutrient network. Ziyantao and Jiuxiang No. 2 can be propagated effectively using cutting techniques, with the 21st day of cuttings identified as a critical regulatory stage. These findings provide a theoretical reference for further exploration of gene mining and regulatory network construction related to adventitious root formation in peach.
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