ENHANCED YIELD OF TOMATO IN RESPONSE TO 2-(3,4-DICHLOROPHENOXY)TRIETHYLAMINE (DCPTA)

Application of the bioregulator, 2-(3,4-dichlorophenoxy)triethylamine (DCPTA) to tomato (Lycopersicon esculentum Mill. cv. Pixie) significantly increased the vegetative growth and fruit-yield productivities of mature plants. Compared with controls, application of 30 μM (10 ppm) DCPTA as a pre-germination seed treatment increased the mean relative growth rates of leaves, stems, and roots, 37%, 16%, and 20%, respectively, during exponential growth. At fruit harvest, the dry weights of leaves, stems, and roots, and the harvestable yield of 30 μM DCPTA-treated plants were doubled when compared with controls. Increases in both the total fruit number per plant and the size of individual fruits contributed to the improved yield of 30 μM DCPTA-treated plants. The total soluble solids contents of mature fruits harvested from 30 μM DCPTA-treated plants were increased 24%, and the lycopene and beta-carotene contents were doubled as compared with controls. These results indicate that DCPTA treatment does not adversely affect the balanced partitioning of photoassimilate to vegetative and reproductive sinks in tomato. © 1990 Kluwer Academic Publishers.