Effect of ROOT-HOR doses on the vegetative propagation of Polylepis racemosa (Ruiz & Pavon) in High-Andean ecosystems of Peru

The restoration of high-Andean ecosystems has become a priority due to increasing environmental degradation, biodiversity loss, and the decline of essential ecosystem services in the mountainous regions of Peru. Among native tree species, Polylepis racemosa Ruiz & Pavon is recognized for its ecological importance in protecting soils, regulating water resources, and conserving high-altitude biodiversity. However, restoration programs are constrained by the limited availability of vigorous seedlings and the low efficiency of vegetative propagation. This study evaluated the effect of different doses of the ROOT-HOR biostimulant on the vegetative propagation of P. racemosa under high-Andean nursery conditions in Ayacucho, Peru. A randomized complete block design was established with six treatments (0, 3, 6, 9, 12, and 15 mL L⁻¹), six replications, and 1,008 cuttings. Survival, morphometric growth, biomass accumulation, and seedling quality were assessed to determine the optimal propagation treatment. Significant differences (p ≤ 0.05) were observed among treatments for survival, stem height, stem diameter, root length, and biomass production. The 6 and 9 mL L⁻¹ doses produced the most favorable responses, with the highest survival rate reaching 61.42% and the greatest mean stem height of 29.13 cm. These treatments also promoted a more balanced distribution of root and shoot biomass, resulting in greater seedling vigor and improved establishment potential. Overall, the application of 6 mL L⁻¹ of ROOT-HOR proved to be the most effective dose, providing a practical and sustainable strategy to enhance the vegetative propagation of P. racemosa and strengthen reforestation and ecological restoration efforts in high-Andean ecosystems.