MÉTODOS DE RESGATE E IDADES CRONOLÓGICAS DE PLANTAS-MATRIZES NO ENRAIZAMENTO DE BROTAÇÕES EPICÓRMICAS DE <i>Ilex paraguariensis</i>

Abstract

RESUMOO objetivo deste trabalho foi verificar o enraizamento de estacas de brotações epicórmicas provenientes de anelamento e decepa de árvores adultas de erva-mate com 17 e 80 anos, no inverno e verão. O plantio foi realizado em caixas preenchidas com vermiculita e casca de arroz carbonizada 1:1 (v/v) e após 90 dias em casa de vegetação, foram avaliados a porcentagem de enraizamento, o número de raízes, o comprimento médio de raízes, a sobrevivência, os calos e a mortalidade. Estacas provenientes de anelamento de árvores de 17 anos apresentam elevada taxa de enraizamento (88,7%), número (13,3) e comprimento médio de raízes (3,3 cm). Palavras-chave: propagação vegetativa; revigoramento/rejuvenescimento; rizogênese. ABSTRACTWe investigate the rooting of epicormic shoots from girdling and coppicing of adult mate trees with 17 and 80-years-old, in the winter and the summer. Cuttings were planted in boxes filled with vermiculite and carbonized rice hull 1:1 (v/v) and after 90 days in greenhouse rooting percentage, number of roots, average root length, survival, callus and mortality were evaluated. Cuttings from girdled trees with 17-years-old showed better rooting (88.7%), number (13.3) and average root length (3.3 cm). Keywords: reinvigoration/rejuvenation; rhizogenesis; vegetative propagation. INTRODUÇÃOA erva-mate é uma cultura de grande importância para os países da América do Sul e seus principais centros de produção e consumo estão localizados na Argentina, Paraguai e no Brasil, especialmente na região Sul, em que apresenta um elevado potencial econômico, social e ecológico (SANTIN et al., 2008). A cultura tem se tornado cada vez mais uma alternativa rentável ao pequeno produtor rural, gerando, além da segurança financeira, uma melhoria nas relações ambientais dentro da propriedade (MALINOVSKI et al., 2006). Entretanto, há ainda a necessidade de estabelecer uma produção contínua 1 Engenheiro Florestal, Dr., Professor do

THREE EPICORMIC SHOOT TECHNIQUES IN I. paraguariensis MOTHER TREES AND ITS CUTTING ACCORDING TO THE MATERIAL REJUVENATION DEGREE

“…The survival of cuttings from aged mother trees that have undergone reinvigoration techniques, such as complete girdling, may be greater than 75.0%. (Stuepp, 2017b). This difference was not found in the present search, where survival for both materials, whether or not reinvigorated, was statistically equal.…”

“…Reinvigoration caused by complete girdling may favours the rooting of cuttings from aged mother trees (80 years) by more than 55.0% (Stuepp et al, 2017b). Cuttings of reinvigorated I. paraguariensis material significantly increase (up to eight times) their rooting (65.5%) compared to the crown (8.5%) (Bitencourt et al, 2009).…”

“…These problems can be solved by obtaining seedlings by vegetative propagation, such as the cutting technique, by selecting genetically superior individuals. Plants produced via vegetative propagation tend to have similar productivity of raw material, since they are clones of the same mother tree (Wendling and Brondani, 2015), facilitating the implementation of management techniques (Wendling et al, 2004) One of the main problems for the success of cutting is strongly related to the ontogenetic age of the plant material, in which the older the material the lower the percentage of rooting of cuttings (Wendling, 2004;Stuepp et al, 2017aStuepp et al, , 2017b. Therefore, it is necessary to use techniques that aim to rejuvenate the vegetal material to be used in the vegetative propagation of I. paraguariensis (Wendling and Brondani, 2015), considering the difficulty of rooting the plant material of lower vigor (Almeida et al, 2007;Brondani et al 2009, Stuepp et al, 2017a, 2017b.…”

Rooting of yerba mate cuttings with different lengths

“…Overall, the stem cuttings used in this study were satisfactory for yerba mate, as observed by other authors (KRATZ et al, 2015;TRONCO et al;STUEPP et al, 2015STUEPP et al, , 2017aSTUEPP et al, , 2017b. The percentage of rooted cuttings ranged from 22.50% to 86.25% among the different treatments.…”

“…Summary of the variance analysis for the percentage of Ilex paraguariensis rooted cuttings (RC), number of roots per cutting (NR), average root length (ARL), callus (C), cuttings with roots and callus (CRC), mortality (M), sprouts (S) and maintained leaves (LM) in relation to cuttings length at 120 days after planting. Several studies have recommended using semi-hardwood stem cuttings with length patterns of 12 cm and a pair of leaves above the last bud (BITENCOURT et al, 2009;STUEPP et al, 2015STUEPP et al, , 2017aSTUEPP et al, , 2017b. However, we question the lack of papers that corroborate information regarding cuttings smaller than 12 cm and their respective rhizogenic potential, seeing a great discrepancy in studies carried out to date regarding the influence of juvenility and vigor of propagules (BITENCOURT et al, 2009;STUEPP et al, 2015STUEPP et al, , 2017aSTUEPP et al, , 2017b.…”