FURTHER STUDIES ON THE CHEMICAL INDUCTION OF PARTHENOCARPY IN THE CALIMYRNA FIG

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Abstract
During the 1948 season, 9 chemicals applied as sprays were studied for induction of parthenocarpy in 2d crop Calimyrna figs. Indole-butyric acid was effective from 200-1500 ppm. with leaf chlorosis above 600 ppm.; naphthaleneacetic acid, increasingly effective from 25-250 ppm., with slight toxicity at 50 ppm. and severe chlorosis at 250 ppm.; 2,4,5-trichlorophenoxyacetic acid, effective as low as 10 ppm., with greatly accelerated fruit maturation. Syconia sprayed with the latter were mature in 14 days whereas pollinated fruit required 75 days. The chemicals also accelerated maturation of pollinated Calimyrna fruit and the normally par-thenocarpic fruit of the Black Mission var., but in all cases caused chlorosis at low concns. and death in about 1 mo. at 75 ppm. Parachlorophenoxyacetic acid at 40-80 ppm. induced partheno-carpic fruit that matured normally and was essentially equal to pollinated fruit in all respects. No injury was apparent from this material at effective concns. All parthenocarpic fruit was devoid of achenes, with no sclerification of ovary walls. Processed parthenocarpic fruit was of good appearance, but milder and somewhat different in flavor from similar caprified fruit.