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INTRODUCTION

Jatropha curcas (Euphorbiaceae) is a plant of commercial importance due to its potential to produce biodiesel from it seeds, which have high oil content. (Sharma et al. 2009; Wang & Ding 2012). Production of J. curcas (JC) biodiesel requires seeds as raw material. Thus, indirectly, production of biodiesel using JC is highly dependent on production of JC flowers, because the seed is produced by hermaphrodite or female flowers.

Generally, JC plant produces both male and female flowers on the same plant (monoecious) (Alam et al. 2011); however sometimes JC might also produce hermaphrodite flowers (Jones & Csurhes 2008; Yi et al. 2010). JC specimens that produce hermaphrodite and male flowers, but not female flowers, are called andromonoecious (Dellaporta & Urrea 1993). Andromonoecious JC rarely found. The JC flower is the unlimited compound flower type (racemosa) with a dichasial branch pattern, where female flowers are located between two male flower branches, on monoecious JC plants (Raju & Ezradanam 2002). In monoecious JC, there are about five female flowers in one inflorescence (Wijaya et al. 2009). The ratio of female to male flowers is about 1:20 (Wu et al. 2011) to 1:29 (Raju & Ezradanam 2002). The low proportion of female flowers in monoecious JC limits fruit production. The low level of fruit production not only results in low seed production, but also causes lack of seed continuity. This problem is the focus of JC improvement efforts (Wahyudi & Wulandari 2007).

Andromonoecious plants were a great opportunity to produce much fruit (Miller & Diggle 2007). In andromonoecious JC, as in other plants, the number of fruit is dependent on the number of hermaphrodite flowers. Based on previous research, andromonoecious JC has the number of hermaphrodite flowers per inflorescence which is low in comparison to male flower (1:15). Nonetheless the potential for high fruit yield is strong. Andromonoecious JC flowers throughout the year and hermaphrodite flowers have high rates of fruit set, reaching 100%. High numbers of hermaphrodite flowers will produce more fruit. Therefore, it is very important to improve hermaphrodite flower production in andromonoecious JC.

The enhancement of hermaphrodite flower production does...

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