A six-parent diallel which included carrot inbreds with a range of carotene content from 80 to 490 ppm was evaluated over 2 years. General combining ability accounted for most of the variation observed. Phenotypic mass selection was exercised for high carotene content in three carrot populations. Response to selection continued to be high in one population, HCM, after 11 cycles of selection. In contrast, after three generations of selection, little progress was able to be made in a population derived from primarily Nantes-type open-pollinated cultivars. Realized heritability estimates varied from 15% to 49%. Environment contributed significantly to variation in carotene content.