CHARACTERIZATION OF TRADITIONAL YAM VARIETIES BELONGING TO THE DIOSCOREA-CAYENENSIS-ROTUNDATA COMPLEX BY THEIR ISOZYMIC PATTERNS

Four hundred and fifty three accessions of cultivated yams collected in West Africa, which belonged to twenty variety groups, on the basis of their morphological characteristics, were studied using starch electrophoresis. A study of polymorphic enzyme systems (malate dehydrogenase (MDH), isocitrate dehydrogenase (ICD), 6-phosphogluconate dehydrogenase (PGD), shikimate dehydrogenase (SDH), and phosphoglucoseisomerase (PGI), revealed sixty two genotypes. Twelve cultivar groups could easily be identified. The results showed a good agreement between morphological polymorphism and enzymatic variation. Morphologically polymorphic varietal groups are polyclonal while monomorphic ones appear to be monoclonal. This implies that, genetic as well as somatic mutations have occurred during the domestication of yams. © 1990 Kluwer Academic Publishers.