ABSTRACTYellow lutescent tomatoes normally devoid of lycopene can be induced to produce this red pigment when treated with bioregulators such as CPTA, (2‐(4‐chlorophenylthio)‐triethylamine hydrochloride). Red light and CPTA combination stimulated the accumulation of 225 μg/g of lycopene in mature white lutescent tomatoes after a 12‐day ripening period. Tomatoes treated with CPTA but ripened in the dark produced 67 μg/g of lycopene. Far‐red light treatment of the CPTA treated tomatoes produced only 25 μg/g of lycopene. Analysis of other carotenoids showed a similar trend indicating a quantitative but not a qualitative change in carotenogenesis in lutescent tomatoes as affected by light and by bioregulators. The antagonistic effect of far‐red light toward CPTA suggested that the two effectors might work at the same reactive site i