Agrobiodiversity in Middle Casamance (South Senegal): collection and agro-morphological assessment of traditional rice landraces

Casamance is the main centre of cultivated traditional rainfed rice in Senegal including Oryza sativa and O. glaberrima species. Traditional landraces are an important source of genetic variability essential for the improvement of elite varieties adapted to local conditions. The study aimed at collecting and characterizing rice accessions cultivated in Middle Casamance. A total of 11 valleys and 29 villages were visited. Based on farmers' perception on agronomic traits, 171 rice accessions were collected and 136 characterized in an open-field trial. Accessions presented a high variability for all the traits assessed (p-value < 0.001) and were grouped into three main clusters based on seven quantitative variables with grain yield and panicle number as the most discriminative traits. Most of the accessions was semi dwarf to intermediate plant type, early to medium flowering, early maturing and with a low to moderate tillering ability. An average overall mean diversity (0.52 +/- 0.21) was observed with the highest in Sindina, Balmadou and Bambali valleys. This study revealed an interesting diversity in the collection, representing a pre-breeding material for future rice improvement programs targeted to Casamance local conditions. It highlights also the significant role played by local farmers in maintaining and shaping local germplasm.