Jatropha Male-to-Female Plant Ratio

Jatropha Plants

• Jatropha is a bush or small tree that grows just under 20 feet tall. It has wide branches with short twigs and deciduous leaves. The stems exude a milky sap when damaged, which may be toxic. The flowers are both male and female and are a lighter green than the foliage. The male flowers have 10 stamens and are joined in groups of five in much higher numbers than the female blooms. The female flowers are single with a three-celled ovary crowned with three stigmata. After fertilization, the females produce green capsules that split into thirds containing black seeds.

Traditional and Modern Uses

• The jatropha plant has a history in Indian folk medicine, where the extract is used for anything from attempting to cure cancer to incontinence. The latex sap is a common topical medicine for stings, bites and burns. A root decoction is used for many oral disorders including toothache. These are just a few of the medical uses of the plant as cited by James A. Duke in an article on jatropha for Purdue University. Jatropha is found as fencing material in many countries but is considered a weed plant in others. Current Science in 2009 claims the seeds as a biofuel can yield 30 to 42 percent of oil content that is compatible with diesel fuel uses. If the female-to-male flower ratio is significantly increased. the high oil content has potential as a commercial oil substitute.

Reproduction

• The female flowers only open for two to four days while males are open for eight to 10. This disparity, coupled with the low female-to-male bloom ratio, minimizes fruit and seed production. The plant is a perennial and flowers in the first year. The first year female flowers are 1:18-30 of male plants produced, but this ratio changes in the second year. Then the production of female plants is 1:9-16. This reduction in number of female flowers is consistent through the life of the plant.

Increasing Female Flowers

• If more female flowers are produced, the plant can create more biofuel, which makes plantation growth more economical. Hybridization is being attempted to create a superior jatropha plant with more female blooms. Growth regulators have some potential to expand production of females and enhance fruit production. Jatropha curcas is the species of plant whose fruits have the most oil. There is also an effort to identify the most high yielding plants and propagate them vegetatively to produce clones with the same characteristics as the parent plant.