Growth and yield of Jatropha curcas L. (Euphorbiaceae) plants cultivated in different spacing and treated with kinetin

Abstract

Recommendations for J. curcas plants were studied for adequate crop spacing, and to increase the number of female and hermaphrodite flowers and fruit yields. The study was carried out in an experimental field in Brazil,using four-year-old adult plants in a 5 x 3 factorial in a completely randomized design with three replications. Treatments included five doses of the growth regulator kinetin (0, 3, 6, 9 and 12 mg L-1 at the volume of 330 ml per plant) in a single application to six plants and three planting spaces (3×3, 3×2, 3×1 m). The results showed that the applied kinetin doses did not interfere in the production index of J. curcas, but population density exerted a significant influence on the vegetative and reproductive development of the J. curcas plants in the 3x3 spacing, where competition for essential growth resources (water, light and nutrients) seems to have been less intense and the plants were more vigorous. Cropping J. curcas plants in 3 × 3 spacing is recommended to obtain vigorous plants with a high number of branches, inflorescences and high grain yield. Applying kinetin at concentrations lower than 12 mg L-1 did not interfere in the sexual expression of J. curcas flowers. Further studies with higher kinetin doses in 3 × 3 m spacing are necessary to elucidate and recommend new management practices.