Impact Of Thermotherapy And Chlorothalonil On Plantlets Production Of Some Genotypes Of Cassava (Manihot Esculenta Crantz) Produce In Benin

Abstract

ABSTRACT: Cassava (Manihot esculenta) is a starchy root plant of great economic importance in sub-Saharan Africa and particularly in Benin. Its production is confronted to virus diseases which cause a considerable losses of yield. This work aims to determine the impact of thermotherapy and chlorothalonil in the production of cassava material of plantation. Cuttings of four varieties: RB89509, BEN86052, 91/02319, 92B/0057 are cultivated under two conditions of thermotherapy and a control under greenhouse during 4 weeks. These different conditions are: a closed drying oven wit h 16 hours photoperiod at 40 °C the day and 36°C the night; a drying oven ―Binder‖ with photoperiod of 12 hours at 38°C the day and 28°C the night and the control carried out under the conditions of the greenhouse. The media used was Murashige and Skoog (MS) added with various amounts of chlorothalonil: 0.6 g/l and 2g/l and control without chlorothalonil. Both techniques of thermotherapy eliminate the virus symptoms of cassava at the rate of 0 seedling infected in thermotherapy against 16 seedlings in natural condition. The technique of closed drying oven signif icantly favors the production of nodes at 5% level (p=0.000) and shoots (p=0.02) on the other hand Binder drying oven has no significant effect on the production of shoots (p=0.68). The chlorothalonil had a positive effect on in vitro infestations elimination of cassava (p<0.05) but influenced the growth and development of cassava explants by reducing of nodes production (p<0.01) without a lethal effect on the plantlets until the dose of 2g/l.