Optimization paths for an on-farm multiplication and sanitation technique for plantain banana | Vias de optimizacion de una tecnica de multiplication y saneamiento para el platano

International audience

English. Plantain banana is of vital importance to the tropic’s food supply. However, banana cropping systems face telluric pests and aerial fungal diseases that affect fruit yield and quality. In an agroecological transition context, the development of prophylactic methods aimed at avoiding the use of pesticides is an avenue to explore. Among these methods, the in vivo mass propagation of shoots technique (PIF technique in French for Plants Issus de Fragment de tige - ‘shoots resulting from corm fragments’), developed in Cameroon to multiply and sanitize plantain shoots at the farm level, has shown promising results, but factors that could improve its efficiency have not been thoroughly studied until now. The objective of this research, carried out in Guadeloupe (French Caribbean), was to measure how different environmental conditions (temperature, light and hormone supplementation) during the reproductive stage affect the efficiency of the PIF technique (number and robustness of daughter shoots). The effects of these three factors were investigate in separate assays within semi-controlled environmental conditions. Five response variables were used to assess the number and the robustness of daughter shoots produced: (i) the number of shoots produced per corm, (ii) the average size of shoots produced per corm (in cm) for shoots longer than 2 centimeters, (iii) the average number of leaves per shoot produced, (iv) the number of roots per corm and (v) the length of the largest corm root (in cm). We found that temperatures above 30°C led to a significantly increase in performance of the PIF technique (>15 shoots per corm, >25 roots per shoot, >80 cm root length). In addition, the experiment also allowed identifying positive effects of LED light (15 minutes per day) and hormone supplementation (5 seconds immersion in a synthetic hormone solution) on the PIF technique performance. Finally, a moderate but significant virus sanitation potential of this technique was found, with up to 36.7% daughter plants sanitized from banana mild mosaic virus (BanMMV) infected mother plants. Altogether, these results open perspectives for larger scale assays to refine an appropriate methodology allowing farmers to become autonomous in healthy planting material satisfying the principles of agroecological transition.