Isozyme variability in West African maize cultivars (Zea mays L)

Enzymatic polymorphism analysis of West African maize was undertaken to describe their isoenzymatic polymorphism, to analyse the factors of the genetic structuration on some landraces, and to study the occur rence of introgression between an introduced elite variety and landraces. Three different materials were analysed on 18 loci: 100 landraces collected from the two types of fields used in Burkina Faso for maize growing, a West African maize gene pool named Composite Y and constituted by 145 flint landraces of six countries, and an improved elite open-pollinated variety (SR 22) delivered by IITA and released in Burkina Faso. The results indicated that the allelic richness of the West African maize was similar to that of European maize but was quite lon,er than what had been found in American maize. Compared with published data, the results indicated that specific frequency of some alleles are observed in maize sample of West Africa; Europe and South western USA. The enzymatic variability of Composite was lower than that of Burkina's maize landraces. The type of fields (bush field and household field) where maize landraces are cultivated was a main factor of genetic structuration among these materials. The existence of gene flow between landraces and the elite variety have been established by the existence of two alleles which are specific to the elite variety. With these alleles, the maize breeders have a mean to control the introgression of elite variety; and to manage the in situ maize genetic variability. The paper discusses the management of maize landraces of West African savannah zone.