Indolbutyric acid on rosemary vegetative propagation

ABSTRACT

Rosemary (Rosmarinus officinalis) is a subshrub sized plant, used as a condiment and for medicinal purposes. The growing demand for drugs derived from rosemary essential oil is attracting interest from research on the propagation of this species. The objective was to evaluate the effect of IBA on vegetative propagation of rosemary cuttings in two seasons. The experiments were carried out in greenhouse during two periods, from November 2010 to January 2011 (summer) and from April to June 2011 (autumn). The experimental design was randomized blocks with four replications and 20 cuttings per replication and treatments were six indole butyric acid concentrations (IBA) (mg/L): 0, 1000, 1500, 2000, 2500 and 3000. The cuttings base was dipped in the respective solutions with and without AIB and were planted in tubes containing commercial substrate Mecplant^(r). The characteristics evaluated in the stem cuttings were height at 7, 14, 21, 28, 35 and 42 days after planting date, rooting percentage, mortality, the longest root length, fresh and dry weight of the aboveground part and roots. The season did not influence significantly rooting and growth of rosemary seedlings. The concentration of 2500 mg/L resulted in higher percentage of rooted cuttings (98%), fresh (0.75 g/plant) and dry aboveground part mass (0.30 g/plant); length of the longest root (15.74 cm), fresh (0.65 g/plant) and dry root mass (0.15 g/plant) over the cuttings without treatment with IBA. The application of IBA on the evaluated concentrations resulted in positive effects for rooting of rosemary cuttings, favoring the growth in height and accumulation of fresh and dry weight of the aboveground part and roots, thus making more efficient rooting, enabling the medicinal plants producer to obtain more developed seedlings in less time.

Keywords:
Rosmarinus officinalis; cutting; auxin; growth regulator