Abstract:Morphological variation and change of chromosome number in the plantlets of potato (Solanum tuberosum L. cv. Xiao Yie Zi × Duo Zi Bai) regenerated from mesophyll protoplasts have been studied. The normal plantlets from protoplasts were similar to parent plants. Their chromosome numbers were 2n = 48±or 2n= 72 of euploid. The plantlets with distinctive phenotypic variation were likely to be aneuploid with increased chromosome numbers.