The genetic relationship between any two populations is a function of the differences between them in allele frequencies, with this relationship commonly expressed in terms of a genetic distance. For example if the two populations are homozygous for different alleles at a particular locus, the distance is the maximum possible whereas if the allele frequencies in the two populations are identical, the distance is zero. The estimated genetic distances may vary among loci. Thus, the most accurate measures of relationships will be obtained by averaging many loci (Nei, 1978). In plant and animal breeding, it is expected that a cross between two individuals originating from two populations with a large genetic distance between them will result in maximum heterosis or hybrid vigour. Many estimates of genetic distances are available in the literature but Nei’s standard genetic distance, D, (Nei, 1972, 1978) had been extensively used in studies of human, animal and plant varieties, races, breeds, strains, populations, species and genera.