An interspecific hybrid Jatropha curcas (Jc) × Jatropha integerrima (Ji) was developed between jatropha (Jc) from Mexico and Ji from Thailand. Jc is a large canopy plant with soft wood, while Ji is a tall plant with semi-hard wood. The F1 hybrid and their parents were grown under field conditions at a spacing of 1 m × 1.5 m. One-year-old plants were harvested and determined for biomass yield, calorific value and chemical composition of wood, as well as for heterosis (hybrid vigour) of these characters. The F1 plants gave an average fresh wood weight of 18.07 kg/plant, a moisture content of 46.56%, a dry wood weight of 9.56 kg/plant and a wood density of 0.62 g/cm3. The F1 hybrid had less ash (2.60%) than Jc (6.93%), but a higher heat value of wood (18.73 MJ/kg) than Jc (17.77 MJ/kg). Heterosis over mid-parent was very high and positive in dry wood weight, fresh wood weight and number of secondary branches at 542, 310 and 450%, respectively, while negative heterosis was found in moisture content ( − 24.86%). The desirable traits found in the F1 hybrid can be fixed by cutting propagation of the selected plants.