Effects of leaflets and indole-3-butyric acid in the vegetative propagation by mini-tunnels of rubber tree (Hevea brasiliensis)

Abstract

Rooting induction of leafy stem cuttings of Hevea brasiliensis can be used as a relevant tool for the cultivation, conservation of genetic diversity, and rescue of this species in Peru, decimated by decades of extractive practices. In this study, we evaluated the effects of different numbers of leaflets and concentrations of indole-3-butyric acid (IBA) in the rooting capacity of leafy stem cuttings of H. brasiliensis. Cuttings 6-7 cm long were collected from stockplants in a germplasm bank; leaves were pruned to 2 or 5 leaflets, and the cutting base was treated with one of the following IBA concentrations: 0, 1000, 2000, 3000, 4000, or 5000 ppm. Cuttings were placed in trays with a sandy substrate and transferred to plastic mini-tunnels with fogging irrigation. After 29 days, cuttings with 5 leaflets and 2000 ppm of IBA showed the best results in survival (100%), rooting percentage (79%), and roots number (4.1) and length (2.9 cm). The high conversion rate of cuttings to plants indicates the feasibility of this technique as a simple and effective tool, both for the conservation and the commercial propagation of selected rubber tree genotypes.