The diagnosis of places of varietal diversity of rice in Guinea was made from survey data from several farms in 41 villages themselves distributed in the 2 natural regions of Lower Guinea and Forest Guinea. The descriptors used are the number of known varieties and varieties cultivated at different scales, as well as their utilization rate. The latter makes it possible to classify the Sativa and Glaberrima varieties at the village level and to identify improved and local varieties of notoriety. Diversity indices derived from the adaptation of parameters used by ecologists to describe biodiversity in the natural environment have made it possible to better understand the risks of loss of diversity. Varietal diversity is very important, particularly in the two regions of old rice-growing tradition, forest Guinea and
lower Guinea. But it is also fragile because of the low rate of use of a large number of varieties and their lack of knowledge. As this structuring of diversity is shaped by the great diversity of agro-systems and the poor control of other production factors by farmers, the risk of loss of diversity seems limited in the current context. The fairly widespread adoption of recently released improved varieties (CK, NERICA and ARICA) does not translate into a reduction in the number of pre-existing crop varieties. Complementary to the latter, in particular by their tolerance to biotic and abiotic stresses (iron toxicity, pyrolysis and drought), they seem to be rather an enrichment of varietal diversity in Guinea.

Varietal diversity, Diversity indices, NERICA, CK, ARICA and iron toxicity