Effect of chitosan on the vegetative propagation of cacao (Theobroma cacao L.) by stem cuttings

Abstract

It is estimated that the world production of cacao (Theobroma cacao L.) in the future will not meet its demand due to factors such as losses derived from pests and diseases, aging trees, limited yields, and effects of climate change. The biostimulant Quitomax®, whose main bioactive ingredient is chitosan, is a growth and resistance inducer, and an antimicrobial agent with promising results in agricultural crops. However, since its effect on the rooting, establishment and growth of cacao has not been investigated, the objective of this work was to evaluate the effect of Quitomax® on two commercial varieties of cacao, and compare it with Raizyner GNS commercial product. The experimental design was a factorial arrangement with the two cacao clones (A) and three chitosan concentrations (100, 500 and 1000 mg L-1) (B), with three replicates per treatment. Untreated plants and plants treated with Raizyner GNS (5000 mg L-1) were used as controls. The biostimulant Quitomax® promoted a significant increase in the vegetative growth variables evaluated in the cacao clones compared with the controls. In regards to plant regeneration, Quitomax® decreased the levels of the unrooted stem cuttings by 18% to 50%. In addition, Quitomax® favored the growth promotion and biostimulation of cacao plants during clonal reproduction by cuttings with better results than those obtained with other commercial products such as Raizyner GNS.