Effects of different concentrations of IBA and IAA on rooting of Thymus kotschyanus Boiss. Cuttings

In order to investigate the morphological reactions of Thymus kotschyanus Boiss. cutting to auxins (IAA and IBA) in different concentrations, an experiment was conducted in 2009 at the greenhouse conditions of Semnan Agriculture and Natural Resources Research Station. This research was conducted as a factorial experiment in a randomized complete block design with 3 replications and 20 observations per replication. The treatments included A: two types of auxin (Indole-acetic acid (IAA) and Indole-3-butyric acid (IBA)) and B: concentrations of auxin, (0, 100, 200, 300, 1000, 2000 and 3000 ppm). The traits studied were the root length and number, the percentage of rooting and dry root weight and new buds in plants. Results showed that the highest root dry weight and the root length were observed in the cuttings treated with 100 and 300 ppm of auxins. These concentrations (100 and 300 ppm) of auxins respectively stimulated root dry weight by about 3.6 and 3.25 times higher than control plants and increased the root length by about 150 and 90 percent more than control cuttings. The highest root length, root number, and number of new buds in the cuttings of Thymus kotschyanus were obtained due to the application of IAA as compared with IBA. Our findings confirm that the cuttings treated with 100 ppm of IAA can produce the highest quality transplants at commercial scale.