Quality of <i>Jatropha curcas</i> L. Seeds Harvested at Different Stages of Fruit Maturation

Abstract

The aim of this study was to evaluate the physiological quality of Jatropha curcas L . seeds harvested at different stages of fruit maturation and two threshing methods. To analyze the mechanical damage rate an experiment was carried out with five stages of fruit maturation (green, yellow, ripe, dried on the ground and dried on the plant) threshed mechanically and manually. To evaluate the physiological quality, three tests were made; germination, vigor and electrical conductivity, all of them were applied in each storage (0, 120 and 240 days after harvest) and five stages of fruit maturation. It was feasible to infer that the maturation stage of yellow, ripe and dried on the plant fruits showed the best results of the physiological quality of the Jatropha curcas L. seeds. The manual threshing is also recommended in order to preserve the physiological quality of Jatropha curcas L. seeds. When the fruits were harvested at the appropriate stage of maturation (yellow, ripe and dry fruit on the plant) and threshing without mechanical damage, the Jatropha curcas L. seeds are possible to store for 240 days without loss in their germination. Regardless of the threshing system and the maturation stage, the seeds of Jatropha curcas L. lost their vigor from 120 days after harvested, when these seeds were stored in the shadow and in an environment without control on the relative humidity and air temperature.