Establishment of jatropha (Jatropha curcas L.) germplasm and their micropropagation

Abstract

Jatropha curcas L. is a commercially important non-edible oilseed crop known for its use as an alternate source of biodiesel. Presently, bio-fuels are being considered as renewable source of energy derived from various biological raw materials. Jatropha species are primarily propagated through seeds; therefore, they are heterozygous in nature. Based on the published reports, it is now known that there is a considerable variation in terms of seed yield and oil content between the different Jatropha species available globally. Usually, oil content varies from 10 - 55 %. It is perennial crop, and proper fruit/seed settings require 3 to 4 years time. The seed viability and rate of germination are low, and quality seed screening is another laborious task. Therefore, propagation of this plant through seed alone cannot provide quality planting material for sustainable production of biodiesel from this crop. To ensure adequate biodiesel production, major challenges include a) findings of elite Jatropha germplasm through survey and selection, b) to produce large number planting materials in a relatively short period of time. Therefore, plant tissue culture techniques using Jatropha germplasm are quite promising. Moreover, such types of techniques are also prerequisite to undertake plant transgenic to produce designer crops with desirable phenotypes. In this context, this project work is quite relevant. In the present investigation, a few plant tissue culture techniques were adopted for establishment of the Jatropha germplasm in the laboratory. First, using suitable media formulations efforts were made to establish embryo culture from few Jatropha accessions. Embryo raised plantlets plantlets were further used for clonal propagation and the growth characteristics were noted. In other attempt, vegetative parts like shoot tip and nodal segments were excised from the field- grown Jatropha plants. After proper surface sterilization, the explants were allowed to grow aseptically on Murashige and Skoog’s medium supplemented with various growth regulators for the purpose of multiple shoot induction. Multiple shoot induction was effected from shoot apices and nodal explants on MS medium supplemented with various growth regulators in different combinations. Multiple shoot induction occurred on MS supplemented with BAP (0.5 - 4 mg/l) and kinetin (0.5 - 4 mg/l) either alone or in combination with IAA (0.5 -1 mg/l). Multiple shoot induction from in vitro embryo culture raised plantlets was effectively initiated on MS medium supplemented with BAP (1 mg/l) + IAA (0.5 mg/l) with an intervening callus phase. Multiple shoot proliferation from shoot tips taken from young field grown plants was best induced on MS medium supplemented with only BAP (1 mg/l). Similarly from in vivo raised nodal segments, initiation of multiple shoot proliferation was observed on MS medium supplemented with BAP (1 mg/l). In conclusion, this study provides useful information for induction of multiple shoot proliferation with the use of different media formulations