Effect of indol-3-butiric acid (IBA) on rooting of cuttings of Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby

Abstract

The propagation of S. amazonicum by seeds can result in uneven seedlings that are subject to poor quality, which is detrimental to uniformity and productivity. The absence of an efficient method of vegetative propagation of the species may be a limitation for genetic improvement, and consequently the increase in productivity of plantation. This study aimed to evaluate the effect of indole-3-butyric acid (IBA) in the rooting of cuttings of paricá - Schizolobium parahyba var. amazonicum (Huber ex Ducke) Barneby. The cuttings obtained from the stems of the seedlings then were treated with IBA in the hydro-alcoholic solutions at 1000, 2000, 3000 and 4000 ppm; commercial product with 2000 ppm IBA powder; commercial product composed of IBA and nutrients; and treatment control (0 ppm). The cuttings were planted in plastic trays with vermiculite and coconut fiber (1:1 v/v) and placed in a box lined with plastic to control moisture. The experimental design was completely randomized with five replications and 10 cuttings per plot. After 60 days, the percentage of rooted cuttings, living and dead, and number and length of roots were analyzed. The analysis of variance at 5% of probability indicated statistical differences for all variables. The best results were observed when we used IBA at 2000 and 3000 ppm, diluted in hydro-alcoholic solutions. These treatments showed statistically equal and produced the highest percentage of rooting, average number and length of roots and lowest percentage of dead cuttings. The polynomial regression analysis indicated that higher rooting rates can be obtained in 2550 ppm of IBA diluted in hydro-alcoholic solutions.