Pré-condicionamento nutricional e resposta ao enraizamento de clones comerciais de Eucalyptus urophylla × E. grandis

Abstract

The production of high-quality seedlings is essential for the successful establishment of clonal eucalyptus plantations. Although mineral nutrition is widely recognized as an important factor influencing root development, little information is available on the rapid immersion of mini-cuttings in nutrient solutions immediately before planting. This study evaluated the effect of this nutritional preconditioning on the rooting performance of four commercial Eucalyptus urophylla × E. grandis clones under commercial nursery conditions. The experiment was conducted independently for each clone using seven treatments, consisting of a control and six combinations of three commercial nutrient formulations applied at two concentrations (40 and 80 mL per 100 L of water). No significant differences in rooting percentage were detected among treatments (p > 0.05). Nevertheless, treated propagules consistently showed numerically higher rooting percentages, particularly when exposed to a nutrient solution containing phosphorus together with macro- and micronutrients, reaching up to 72% rooting. Variation among clones was substantially greater than variation among treatments, highlighting the strong influence of genotype on adventitious root formation. Under the conditions evaluated, rapid nutritional preconditioning by immersion did not significantly affect rooting percentage, providing the first evidence regarding this practice under operational mini-cutting propagation systems. However, the simplicity and operational feasibility of the technique suggest potential practical value and warrant further investigation under more sensitive experimental conditions, including additional clones, different immersion periods, and comprehensive assessments of root system quality.