Cytokinins have proven to be the most promising growthregulator in increasing the total flower number and seeds. Benzyl adenine (BA)and thidiazuron treatment resulted in a drastic increase in number of flowersand female flowers along with induced bisexual flowers in J. curcas (Pan et al. 2011; Pan et al.
2016). However, the fruiting rate wasrelatively low i.e. 2-3 folds as compared to increased female flowers with upto9-10 folds. Also, there was a reduction in 100 seed weight in fruits formedafter cytokinin treatment (Pan et al. 2011; Chen et al. 2014). This reductionin seed weight led to compromised seed yield even after the application of phytohormonessuch as cytokinins.
Apart from Jatropha, reduction in seed yield aftercytokinin application has also been reported in other plant species such assoybean, jojoba and lupin (Maet al. 1998; Nagel et al. 2001; Prat et al. 2008).
However, the reasons for reduction in seed yield have notbeen investigated. We hypothesize that the compromised seed yield could be aconsequence of the inability of the photosynthetic source to fully support sinki.e. seed development in spite of having significantly increased number offlowers. The reduction in final seed formation is also due toabortion of floral buds in cytokinin treated plants at later stages ofdevelopment because all female flowers do not transit to formation of fruitsdue to higher flower abortion rate, which may be due to non-fulfillment ofincreased requirement of sink (Pan et al. 2016; Yashima et al.
2005). Limitedsupply of photo assimilates to increased flowers is due to increasedcompetition among leaves, stems, nodules and reproductive organs which might bethe possible reasons for flower abortion (Brun and Betts 1984; Antos andWiebold 1984). Also, the negativecorrelation between fruiting rate and seed formation with the number of femaleand bisexual flowers per inflorescence on plants treated with cytokinins, maybe a result of either the shortage of photosynthetic products or reduced sourceto sink strength (Pan et al. 2011; Pan et al.
2016). Apart from ex