The objective of the present work was to evaluate the effect of plant growth regulators (PGR) on the vegetative development and productivity of Jatropha curcas plants. A field experiment was conducted at the Goiás State University, Brazil, using two-year-old J. curcas plants planted with spacing of 3 × 2 m, using foliar applications of two PGR—trinexapac-ethyl and prohexadione-Ca. A randomized block design was used with four treatments (trinexapac-ethyl at 1 ml plant-1—T1; prohexadione-Ca at 2 mg plant-1—T2; trinexapac-ethyl at 1 ml plant-1 plus prohexadione-Ca at 2 mg plant-1—T3; and Control—T4), five replications, and plots consisting of two plants. Two applications of a 300 ml plant-1 solution with the treatments were performed with a 30-day interval after the leaf emergence period (late September and October 2017). The trinexapac-ethyl and prohexadione-Ca plant growth regulators increased the grain yield of Jatropha curcas plants by increasing their vegetative growth, and number of inflorescences, and female and hermaphrodite flowers, but had no effect on the uniformity of fruit maturation. The treatment in which both plant growth regulators were used presented the best results, generating more vigorous and productive plants.

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