METHOD: Chemical Assay CONDITIONS: Green House METHOD NARR: Upon maturity, the tubers of chosen accessions were harvested and processed for melanin formation and PPO activity. Crosses of hjt clones showing low melanin formationcultivated diploid potatoes were conducted. Degree of dominance was measured and PPO rate was calculated. RESULTS NARR: Melanin formation showed a pattern different from PPO activity. Between-accession variation was signor melanin. There is considerable within-accession variation, producing mean differences that are significantly different within accessions for both traits. Genetic control of factors responsible for very low PPO and lack of eented together in hybrids is dominant to the higher melanin formation and higher PPO activity in the cultivated parent. AUTHOR EXPLANATION: A large reduction of PPO activity in the tubers may reduce melanin production.