Desenvolvimento radicular e da parte aérea de estacas de goiabeira, com utilização de bioestimulantes comerciais e ácido indolbutírico

Abstract

Vegetative propagation by cuttings is widely used in the production of guava seedlings (Psidium guajava L.); however, it presents physiological limitations related to rooting and the initial development of cuttings. Therefore, the objective of this study was to evaluate the root and shoot development of cuttings from four guava cultivars using commercial biostimulant products associated with indolebutyric acid (IBA). Two experiments were conducted between February and March 2025, in the seedling nursery of the State University of Western Paraná (Unioeste). Experiment I was conducted in a randomized block design, in a 4 × 4 factorial scheme (4 cultivars: Tailandesa, Paluma, Século 21 and Pedro Sato × 4 rooting treatments (IBA, IBA + ComposFix®, IBA + BioRaiz® and IBA + humic acid), with three replications and 20 cuttings per plot. For experiment II, the same design applied in the first experiment was used, in a 2 × 4 factorial scheme (2 Bacillus types × 4 product concentrations: 0, 50, 75 and 100 mL), with three replications, each replication composed of 15 cuttings, totaling 360 cuttings. The cuttings in both experiments were treated with IBA in a hydroalcoholic solution at 6,000 mg L⁻¹, by quick immersion of the base, and conducted in seedbeds containing washed sand under a protected environment. After 70 days, the percentage of rooted cuttings, number of roots, length of the longest root, number of calluses, number of shoots, shoot length, shoot diameter, and number of leaves were evaluated. The percentage of rooted cuttings did not differ statistically among treatments, although the observed values were satisfactory. It is concluded that biostimulants associated with IBA mainly influence the initial vegetative growth of cuttings, while IBA favors the development of the root system of the cultivar Paluma. The use of biological products associated with indolebutyric acid influenced the initial development of guava cuttings cv. Tailandesa, with responses dependent on the microorganism, with Bacillus subtilis standing out in the early stages of rooting.