Effects of chitosan on vegetative organs growth and peroxidases activities in cassava (Manihot esculenta Crantz) cultivars YACE, 9620A, TMS4(2)1425 and TMS30572

In this work, the influence of chitosan on vegetative organs growth and peroxidases activities in cassava (Manihot esculenta, Euphorbiaceae) plants grown in hydroponic was studied. The experiment was carried out under a greenhouse lit by natural light at the Ecology Research Center (Côte d’Ivoire). Six concentrations of chitosan (0, 25, 50, 75, 100 and 125 mg L -1 ) added to the culture media were tested on four cassava cultivars (Yace, 9620A, TMS4(2)1425 and TMS30572). These media are renewed every 15 days and growth of the plants lasted two months. The results showed that chitosan stimulated the growth of 1.1 to 1.4 according to cultivars and organs. Peroxidases activities were 1.5 to 2.6 times higher in leaves and roots in presence of 75 or 100 mg L -1 of chitosan depending on the cultivars. This activity is multiplied by 2.3 to 2.6 respectively in leaves and roots of Yacé, 2.6 and 1.5 of TMS30572, 1.9 and 2.2 of TMS4(2)1425. In 9620A, this factor was less than 2. These results show that chitosan could be a biostimulator in cassava.