Biodiversity and Conservation 2,627-636 (1993) Genetic variability among sorghum accessions from the Sahelian agroecological region of Burkina Faso JEAN-DIDIER ZONGO* lnstitut du D~veloppement Rural, Universit~ de Ouagadougou 03, BP 7021, Ouagadougou 03, Burkina Faso, West Africa PIERRE HENRI GOUYON and MICHEL SANDMEIER Laboratoire d'Evolution et Syst~rnatique V~gdtale, Universit( Paris-Sud X I Bat: 362-91405 Orsay, France Received 17 January 1993; revised and accepted 11 May 1993 The authors collected Sahelian sorghum landraces of Burkina Faso in 1984 and 74 of these accessions were characterized in 1985-1986 at Gampela in Burkina Faso (West Africa). The five races of cultivated sorghum were represented in this zone but 63.5% of the accessions were Guinea type. Great intra- and inter-accession variability was found. Plants were tall and had long panicles and small to intermediate seeds. There was a strong association between days-to-flowering, number of internodes, panicle length and height. The 100-kernel weight showed an antagonism with days to flowering and tillering. Multivariate analyses were made which enabled the accessions to be classified into four groups. The group most adapted to the sahelian zone, 'sahelian group', was semi-late, developed intermediate size of vegetative organs, had moderate tillering and had the best yield per plant. Keywords: Sorghum bicolor; landraces; genetic diversity; characterization Introduction Rapid erosion of genetic diversity has occurred in most cultivated crop species as a result of both natural and artificial selection. This erosion presents unacceptable risks for the production of crop commodities (Harlan and de Wet, 1972). This situation has prompted the creation of several national and international agencies to coordinate, intensify and rationalize the collection, classification and conservation of phytogenetic resources. Sorghum (Sorghum bicolor (L.) Moench) is one of the remaining few crop species with extensive genetic variability. Pioneering collection and evaluation efforts brought to light the need for a universal system for designating the variety of botanical and morphologi- cal forms of the sorghum plant (Snowden, 1936). Murthy et al. (1967) classified the world sorghum collection on the basis of genetic divergences. Curtis (1967) evaluated Nigerian sorghums and Scheuring et al. (1980) evaluated the Malian sorghums. Harlan and de Wet *To whom correspondence should be addressed. 0960-3115 © 1993 Chapman & Hall