Applications of growth regulators and modifications of light exposures were investigated regarding their abilities to curtail the normal development of chlorophyll and glycoalkaloids in potato tubers responding to light . Four growth regulators were sprayed on the foliage of potato plants 14 days prior to harvest, of which two I (Ethephon and N6 -Benzyladenine [N6BA]) successfully retarded chlorophyll and glycoalkaloids in the harvested tubers. When tubers were dipped in N6BA, lower concentrations of the !chemical promoted glycoalkaloid formation, while larger amounts we~e more inhibitory . When fluorescent lights were directed through colored cellophane filters, tubers receiving yellow and orange illuminations were inhibited in chlorophyll formation and those receiving green illumination were most reduced in production of glycoalkaloids .