Factors Influencing Petaloidy Expression in the Carrot, Daucus carota L.1

Abstract

Several vernalized lots of petaloid male sterile carrots were grown under 3 temperature regimes ranging from 50-80°F. The degree of petaloidy increased as temperature increased. Variable petaloid morphology within plants, within umbels, and within single flowers was probably caused by variation in microenvironmental factors. Externally applied chemicals neither promoted nor retarded petaloidy. Transmission across a graft union of the factors responsible for petaloidy expression was not detected.