Abstract
A technique for the isoelectric focussing of soluble peroxidase and acid phosphatase isoenzymes of yams is described. It was found suitable for the positive identification of shoot culture materials of the four yam species, Dioscorea alata, D. cayenensis/D.rotundata, D. esculenta and D. bulbifera. It was sufficiently sensitive to detect differences between four clones of D. alata which were otherwise difficult to distinguish with certainty on the basis of morphological characteristics alone. The described method would be also suitable for the positive identification of somatic hybrids obtained between some of the D. alata clones and the three other species of yam following protoplast fusion and the regeneration of hybrid plants from microcalluses.