Efecto de la luz roja lejana en el enraizamiento de estacas provenientes de plantas madre de dos clones de Eucalyptus dunnii

Currently, 1,085,000 hectares in the country are allocated to forestry use, with more than a quarter dedicated to the species Eucalyptus dunnii. Despite its good wood properties, rapid growth, and frost resistance, it is recalcitrant to rooting, which limits its clonal propagation. This study aimed to analyze how far-red light (FRL) supplementation in mother plants of E. dunnii influences the rooting of cuttings and shoot production. Adventitious rhizogenesis is primarily regulated by auxin and carbohydrate levels, which can be modulated by the mother plants growing environment. Recent studies have shown that light in the 700-800 nm range can promote adventitious rooting. Five variables were evaluated: the number of shoots produced per mother plant, rooting percentage, overall productivity, cutting survival and soluble carbohydrate and starch content at the base of the cuttings. For this purpose, 1.5-years-old mother plants of two Eucalyptus dunnii clones (Clone A and B) were grown in controlled-environment chambers, from which mini-cuttings were taken after one month of RL treatment. The results showed that RL supplementation affects overall productivity by modifying shoot production and rooting percentage. In clone B, the rooting percentage increased from 26% to 40%, representing a 52% increase, along with a 62% rise in shoot number. In contrast, Clone A showed no change in shoot production between treatments and experienced a 55% decrease in rooting percentage. This suggests that the treatment's success depends specifically on the genetic material used. Regarding survival, cuttings from RL treated plants had higher survival rates, indicating that a longer rooting period could influence the outcome. The carbohydrate content at the base of the cuttings at the time of cutting was not related to productivity, meaning this variable is not a reliable predictor of rooting under these conditions. The findings provide useful insights into managing light quality as a tool to improve performance in recalcitrant species within vegetative propagation systems.