PIGMENTS OF PINK GRAPEFRUITS, CITRUS GRANDIS (L., OSBECK)

Abstract

The history of the origin of pink grapefruits is interesting in that they were not developed as crosses by plant breeding, but were derived as bud sports from the ordinary types of grapefruit trees.An account of the origin of two of these fruits, namely Foster and Marsh (also known as Thompson) pink grapefruits, is given in Hume (l), while the origin of a third variety, called Ruby, is discussed by Welch (2).The Foster variety originated from a Walters grapefruit at Manavista, Florida, in 1907.It does not differ materially from the Walters, except in flesh color and in its earlier maturity.The flesh color of the Foster, which is pink, is confined chiefly to the section membranes and often shows through the rind.Two forms of the Marsh pink variety originated as bud sports from ordinary Marsh grapefruit trees, one in Florida in 1913, and the other in California about 1919.Both fruits seem to be typical Marsh grapefruit except in the color of the flesh, which approaches a salmon-pink.The Ruby variety was derived in 1929 as a bud sport from a Marsh pink grapefruit grown in Texas.It is characterized by a red-colored flesh.Only the Foster and Marsh fruits were employed in the present investigation.The presence of lycopene, one of the pigments found as a result of this study, in Florida pink grapefruit has been previously reported by the author (3).In order to confirm his finding and also to identify any other pigment which might be present, a more painstaking study of the coloring matters was undertaken.