THE EFFECT OF CULTIVAR, MATURITY AND STORAGE ON PHOTOINDUCED CHANGES IN THE TOTAL GLYCOALKALOID AND CHLOROPHYLL CONTENTS OF POTATOES (SOLANUM-TUBEROSUM)

The tubers of 20 potato genotypes were exposed to light, equivalent to a radiant flux density of 140 mu mol(-1) s(-1) m(-2), approximating to dull daylight conditions, for a continuous period of 48 h. Tubers were exposed when immature, mature and also after a period of storage. There were significant differences between the genotypes in their rates of increase of both glycoalkaloid and chlorophyll contents. Notably, potato genotypes responded differently to light in their rates of glycoalkaloid and chlorophyll synthesis, this being dependent on the physiological state of the tubers as well as their inherent characteristics.