THE USE OF GROWTH-REGULATING CHEMICALS TO INDUCE PARTHENOCARPIC FRUIT IN THE CALIMYRNA FIG

Abstract

Certain varieties of many species of plants develop their fruits parthenocarpically or without fertilization. The apple and pear occasionally produce parthenocarpic fruits but generally under special nutritive conditions (10). In some varieties of grapes, figs, bananas, and oranges, parthenocarpy is of great economic importance (4,14). Because of this naturally occurring phenomenon, attention has been directed toward inducing parthenocarpy in other fruits and vegetables by the application of hormones of various synthetic growth-regulating substances. Early investigations by Gustafson (9) on chemically-induced parthenocarpy stimulated research in this field and, at the present time, it is possible to produce parthenocarpically several different vegetables, as well as fruits of some ornamental plants. Similar attempts to increase fruit set or to induce seedlessness in some of our more important tree crops, such as the apple, orange, and grapefruit (1, 8, 11, 15) have failed entirely. A review of literature has revealed that all attempts to promote parthenocarpic fruit development in a temperate zone commercial tree fruit, where it did not already occur naturally, have been unsuccessful. This paper presents the results of preliminary experiments that were successful in chemically inducing parthenocarpic development of fruit of the Calimyrna