Strategies and approaches to mangrove swamp rice varietal improvement in west Africa

West African Mangrove swamps are located on the flood plains of rivers and creeks and along the Atlantic coast. The environment is highly variable in terms of rainfall, soil and environmental stresses. In 1976, the West Africa Rice Development Association (WARDA) initiated a mangrove swamp rice varietal improvement programme. Although some progress has been achieved, it is necessary to put in place strategies and approaches to consolidate these results. Any varietal improvement programme for mangrove swamps in West Africa should distinguish two classes of swamps: high rainfall belt or wet mangrove swamps and low rainfall belt or dry mangrove swamps. In high rainfall zones (Guinea, Sierra Leone, Nigeria) selection of short, medium, and long duration varieties of good grain quality should be emphasised. In dry zones (Senegal, Gambia, northern Guinea-Bissau), however, selecting short duration varieties, with multiple stress tolerance (salinity, sulphate acidity, drought and blast) will be essential. Environmental as well as socio-economic characterisation is important and should be undertaken on country basis. A lot of information could be obtained from a systematic collection of all local and improved varieties grown by farmers in the region through national research programmes. Characterising these varieties will help define farmers' preferences in terms of plant type, growth duration, environmental stress tolerance, as well as grain and cooking quality. Les marais de mangrove en Afrique de l'Ouest sont situes dans des plaines inondees de fleuves et de rivieres tout au long de la cte atlantique. Ce milieu est tres variable en terme de pluviometrie, sol et condition du milieu. En 1976, l'Association pour le Developpement de la Riziculture en Afrique de l'Ouest (A.D.R.A.O.) avait initie un programme d'amelioration du riz de mangrove. Bien qu'un progres certain aie ete realise, il convient de mettre en place une approche strategique de l'amelioration varietale afin de consolider ces acquis. Pour cela, tout programme d'amelioration varietale doit distinguer deux classes de marais de mangrove: marais de zones seches et marais de zones humides. Ainsi les objectifs de selection doivent differer selon les zones. Dans les zones humides (Guinee, Sierra Leone, Nigeria), les varietes de cycle court, moyen ou long de bonne qualite seront mieux adaptees. Les cycles courts doivent avoir une certaine resistance a la salinite tandis que dans les zones seches (Senegal, Gambi