Endogenous Knowledge and Morphological Characterization of Cassava (<i>Manihot esculenta</i> Crantz) Accessions Found in Some Agricultural Areas of Gabon

Cassava is a food crop that contributes to food security and is well established in Gabon. Taking into account endogenous knowledge and the dynamics of accessions agrobiodiversity at national level is necessary to undertake conservation strategies to reduce genetic erosion. Based on a participatory survey approach with field visits and data collection, 43 villages spread over seven (7) departments comprising 13 socio-cultural groups were surveyed. In the villages surveyed, 82.75% of cassava cultivation is carried out by women and 54.55% by farmers under 55 years of age. Of the 110 farms visited, 93.64% are individual farms and 6.36% are cooperatives found exclusively in the provinces of Woleu Ntem and Nyanga. The areas under individual use are less than 1 ha, compared with 5 - 22 ha for cooperatives. The harvest is done from 6 months for early accessions and 12 months for late ones. As for the cuttings, it is done in old plantations aged 8 to 12 months. A main component analysis (PCA) although low (22.50%) confirms morphological variability. In addition to the major descriptors (color of the apical leaf, color of the main rib, color of the petiole and sometimes color of the terminal branch), endogenous knowledge of cassava accessions is based on the phenotypic characteristics, the place of origin or on the introducer of the accession in the locality. The Hierarchical Ascending Classification (AHC) has allowed the structure of these accessions in 3 groups of morphological diversity. Group 1 consists of accessions with a small first branching height (90˚). Group 2 comprises individuals with a larger first branching height (>1.35 m) and a low branching angle (<90˚). In the third group, accessions are mainly characterized by the absence of branching. The identification of these different groups offers a great opportunity for the creation of improved cassava varieties in Gabon.