Enraizamento de miniestacas e parâmetros de validação de clones de ipê-roxo para a propagação vegetativa

Abstract

The objective of this work was to evaluate the influence of shoot length, size and leaf area of minicuttings, application of indolebutyric acid (IBA) and to estimate the Pearson correlation and genetic parameters coefficients of characters of the adventitious rooting of ipe-roxo – Handroanthus heptaphyllus (Vell.) Mattos. In the first experiment, shoots were sectioned in minicuttings of 3 cm in length, with 100%, 50%, 35% or 0% of the original leaf area and treated with 0, 500, 1000 or 2000 mg L-1 of IBA. In the second experiment, shoots were separated into three size classes: I (between 5 and 20 cm), II (between 21 and 40 cm) and III (between 41 and 60 cm), and sectioned in minicuttings of 1,3 and 5 cm in length with a pair of leaves reduced to 50% of the original area. The minicuttings were evaluated for the percentages of survival and rooting, number and length of roots. In the third experiment, the genetic parameters were estimated for seven collection of nine clones of ipe-roxo. The minicuttings were rooted in 110 cm³ tubes containing commercial substrate and vermiculite (1: 2 v / v). After 45 days, the number of rooted minicuttings and the percentage of rooting were determined. The leaf area is necessary for the survival and rooting of minicuttings, but IBA is not necessary for rooting. Minicuttings of ipe-roxo with 5 cm are competent for rooting and can be prepared from shoots up to 40 cm in length. The number of rooted minicuttings showed a high linear correlation with the number of produced minicuttings and rooting percentages. The increase of the number of collections is accompanied by an increase in the coefficient of determination, accuracy and selective efficiency, which reach 80% of the maximum coefficient of determination, high precision and selective efficiency in the fourth collection. The genetic parameters confirm the superiority of the ipe-roxo clones used in vegetative propagation. The length and size of minicuttings and the presence of leaves affect plantlet production of ipe-roxo by minicutting.