FLOWER CHARACTERISTICS AND PHENOLOGY OF ANDROMONOECIOUS JATROPHA CURCAS

 

DASUMIATI^1.3, MIFTAHUDIN²*, TRIADIATI² AND ALEX HARTANA²

 

Abstract: Andromonoecious Jatropha curcas (Jatropha) has male and hermaphrodite flowers in one inflorescence. Jatropha is a potential source for biofuel raw material. The development of this plant has various constraints, such as lower fruit set that causes low seed productivity. The existence of andromonoecious Jatropha with high fruit set provides a great opportunity to overcome the obstacles. Understanding floral biology is a requirement for developing a high fruit set andromonoecious Jatropha. This study was aimed at understanding the flower’s characteristics and phenology. The andromonoecious Jatropha flower’s characteristics, number and viability of pollen, and phenology were observed and compared to those of monoecious Jatropha. Andromonoecious Jatropha had inflorescence with a dichasial cyme pattern. An inflorescence produced two main branches and several secondary and tertiary branches, where a hermaphrodite flower was found at whose ends. The number of inflorescence branches in andromonoecious Jatropha was higher than that of monoecious Jatropha. The diameter and size of the sepal and stalk in hermaphrodite flowers were found to be larger than those in male and female flowers. The development of andromonoecious Jatropha flowers was divided into 4 phases, namely initiation (0-3 dai = days after initiation), small bud (3-7 dai), large bud (7-20 dai), and flower blooming (20-39 dai) phases. The anthesis and anther dehiscence of hermaphrodite flowers occurred at the same time between 06:00 to 06:59 am, facilitating self-pollination of the hermaphrodite flowers. The average pollen viability during the anthesis phase was 96.26%, and 88.79% of them survived until the next day.

 

Key words: Flower, Jatropha, Phenology.