Current research and expected practical outcomes for the management of white yam (Dioscorea Alata) anthracnose
Résumé
Climatic changes are expected to bring a number of challenges to agriculture, among which the necessity to prevent the emergence, or to adapt to epidemic dynamics of pests and diseases. In this context, research needs to switch from disciplinary to interdisciplinary approaches and provide global tools to agriculture for successful, sustainable pest management. At the French National Institute for Agronomic Research based in Guadeloupe, researchers from different fields, from geneticians to social economists, are currently involved in a common program aimed at developing a sustainable, environmentally friendly, high performance agricultural systems based on white yam (Dioscorea alata). One of the two most important constraints to white yam production is anthracnose caused by the aerially dispersed fungus Colletotrichum gloeosporioides. In the past, measures to control this disease (by the use of host resistance and chemical pesticides) have lost their efficiency because the adaptive capabilities of the pathogen were not taken into account. We present our current research project, in which we try to better understand the interactions between the plant, the climatic variables at canopy level, and the pathogen, and use this knowledge to develop new strategies for crop protection. We studied the genetics of host resistance and developed a map of quantitative resistance traits, in order to help breeding for new resistant cultivars combining agronomical qualities and sustainable resistance. In order to hamper the pathogen's capabilities to take over resistances, we use mathematical modeling and experiments to study how microclimatic conditions at the canopy level can be modified by practices, providing conditions less favorable for dispersal, survival and multiplication of the fungus. Ultimately, we hope to promote a reasoned use of resistant varieties, and include new practices that can be adopted by yam growers in an environmentally and economically performing agricultural system.