Morphological characteristics of cacao seedlings treated with the bioactivator thiamethoxam

This work aimed to investigate the effect of thiamethoxam on the growth and quality of seedlings obtained through orthotropic cocoa cuttings. A completely randomized design, in a 4x4 factorial, was used, where the treatments were composed of concentrations of thiamethoxam diluted in water (0, 1, 2 and 4 g L-1) and immersion times of the cuttings (0, 15, 30 and 60 min), with six replications and one plant per experimental plot. The following characteristics were evaluated: shoot length, shoot diameter, number of leaves, number of roots, root length, leaf dry mass, shoot dry mass, cutting dry mass, aboveground dry mass, total root dry mass, main root dry mass, secondary root dry mass and Dickson's quality index. The results indicated that, except for the number and length of roots, thiamethoxam improved the other morphological characteristics of the seedlings, with doses between 2.0 and 2.2 g L-1 promoted the best seedling growth under the experimental conditions evaluated. To obtain greater shoot dry mass, the best dose of thiamethoxam was 1.71 g L-1. It is concluded that thiamethoxam can be an effective bioactivator in the propagation of cocoa by cuttings, favoring the growth of seedlings.