Propagação de erva-mate por estaquia: enraizamento, respostas metabólicas ao ácido indolbutírico (AIB) e desenvolvimento de mudas após o plantio

Abstract

The propagation by cuttings is one of the alternatives to obtain uniform and productive herbal. The indolbutyric acid (IBA) has shown to be effective in inducing roots, but there is evidence to cause stress effects or toxicity symptoms. The work consisted of three studies, initially evaluating the effect of IBA doses (0, 3,000, 6,000 and 9,000 mg L-1) in the cutting of five genotypes, called G4, G15, 3G25, G28 and G29. In the second study, with the same genotypes and doses of IBA, they were investigated in the first 18 days of cutting, possible changes in peroxidase activity, sugar levels and total soluble protein, the stems and leaves of the cuttings. In the third study we followed in the development after planting seedlings from cuttings of 13 yerba mate genotypes Cambona 4 seed and seedlings. The results showed that the use of IBA, depending on the genotype, reduces the leaf retention, survival and rooting, especially at higher doses, and leaf retention is essential for survival and rooting. The critical period, depending on the genotype and the use or not of IBA, extends to the fourth or fifth week after cutting. Changes in the levels of proteins, sugars, and especially of peroxidase activity, confirming the hypothesis that the cuttings are subjected to an initial period of high stress. Depending on the genotype and dose, the use of IBA can provide a higher degree of stress or phytotoxic effect. The G4 genotypes and G28, with up to 77.8% and 66.7% of rooting, respectively, had the potential to be recommended as arrays. In the field, the development of seedlings from cuttings ranged between genotypes Cambona 4, and the growth of the best was similar or superior to the seeds of plants, demonstrating the technical feasibility of cloning in the production of seedlings.