ANNOUNCEMENTS
The present study was conducted with the following aims and objectives:
• Analysis of genetic diversity and identification of core accessions: A total of 192 accessions were used for genetic diversity analysis. Further oil content analysis was also carried out with the help of Soxhlet apparatus. The current study revealed that the overall genetic diversity among Indian accessions is extremely low. Oil content in these accessions varied from 11.2% to 51% with mean oil content of 33.5%. The study also suggests that efforts are required to increase the genetic diversity of J. curcas through inter-specific hybridization, mutagenesis and world-wide exchange of germplasm especially from regions of its genetic diversity. An important outcome of genetic diversity analysis was the identification of 16 core accessions which harbored the entire allelic diversity of the germplasm collection with respect to the sampled AFLP loci and oil content variation. These accessions can be used as donors for various desirable traits such as dwarf plant height, large fruit size in future breeding programs.
• Generation of a BC1 mapping population through interspecific hybridization and development of a linkage map: This work led to development of a framework linkage map containing AFLP and microsatellite markers in Jatropha. The density of markers is sufficient to carry out QTL mapping using interval mapping approach which will open the possibility of marker assisted breeding in Jatropha. Further, a novel BC1 population with regard to several desirable traits such as oil content, stem hardness, canopy structure, and flowering window was generated which will act as the base for future genetic improvement of Jatropha. A number of individuals have already been used to generate advance breeding populations.
• Development of microsatellite markers: In the present study, 180 microsatellite loci were isolated and sequences submitted to GenBank. Moreover, the positions of 40 of these markers have already been established through linkage mapping so that these can be easily used by other laboratories. The cross species transferability of these markers shows their potential in similar applications involving other species of the family- Euphorbiaceae, especially, E. officinalis and P. niruri, where very few microsatellite markers are available so far.
• Estimation of outcrossing rates: Jatropha is believed to be an outcrossed species due to its unisexual flowers. The estimates of outcrossing rates based on AFLP and SSR alleles showed that outcrossing (97.7%) is the predominant mode of reproduction on Jatropha. As a departure from several previous reports, no evidence of occurrence of apomixis could be obtained in this study.
• Changes in lipid profiles at different developmental stages of seed development: The study revealed significant changes in fatty acid composition during seed development. Biodiesel with high monounsaturated fatty acid content (Oleic acid) has excellent characteristics with respect to ignition quality, nitrogen oxides (NOx) emissions and fuel stability. In this study, a remarkable increase in oleic acid was observed at stage 8 which suggests that harvesting Jatropha seeds at yellow ripe stage (stage 7) may lead to loss of quality of the biodiesel. The study also generated the basic information which will help in understanding the regulation of biochemical and developmental pathways in Jatropha during seed development using modern genomics tools.
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