Selection of interspecific hybrids (O. sativa x O. glaberrima) or lowland NERICAs and intraspecifics adapted to rainfed lowland growing conditions

摘要

Rice production potential in lowland ecologies is increasingly threatened by weed pressure and other biotic constraints. To face the problems of weed competitiveness, the majority of farmers only have access to manual weeding methods which require a lot of manual labour in a limited time period. Social changes in rural regions - in particular a pronounced population exodus - have meant that manual weeding operations have become irregular: farmers' efforts are penalized resulting in major losses in rice production. In the face of this negative situation, WARDA (The Africa Rice Center) scientists took up the challenge to develop a farming system more adapted to lowland ecologies, flexible in the use of manual labour, requiring a minimum of investment,and ensuring the food security of the rural population. Such a system is centred on the development of plant material with horizontal resistance to the biotic constraints of this environment where such varieties are not usually used (Dingkuhn and Randolph, 1996).