Traditional ecological knowledge, field and molecular evaluation of Jatropha curcas (L.) accessions from Ghana.

Jatropha curcas L. production as a potential source of alternative fuel has gained popularity in Ghana. The government is collaborating with the private sector to develop about one (1) million hectares of Jatropha plantation throughout the country in the next 5-6 years. The questions left unanswered are: why will farmers grow Jatropha? What knowledge do farmers have about the plant? Where will the farmers source quality planting material from? It is likely farmers might have practical knowledge of the use of the plant which will be vital to researchers. Also it is likely there are variations in the local germplasm which can be used as a basis for improvement. The main objective of the study was to determine if there are variations or otherwise in J. curcas accessions collected from 10 regions of Ghana and to identify promising accessions for future genetic improvement work. To begin, a sociological survey on the Traditional Ecological Knowledge of the plant was conducted in all the ten regions of the country. It was identified that J. curcas was among the ten most important indigenous tree species in nine (9) out of the ten regions. It is mainly used for medicinal purposes and mostly found around homesteads. The farmers were aware that the plant can be used for bio-diesel production and showed interest to produce it for sale. Ninety (90) accessions collected from the ten regions of the country were planted in the field and evaluated for growth and yield performance. The analysis of data after ten months revealed that there were significant differences (P≤ 0.05) in the plant height, stem girth, number of branches, number of days to 50% flowering, number of fruits per cluster, fruit and seed yields of the accessions. These suggested variations in the germplasm used for the study. However, due to the shorter duration of the field evaluation, there was the need to employ further studies to gather additional evidence on the variations in the germplasm. Molecular studies were therefore employed to provide an environmentally independent result to confirm the above results. Forty (40) accessions were selected based on the seed yield performance and the site (Regions) where the accessions were collected for the studies. Random Amplified Polymorphic DNA (RAPD) analysis on the forty (40) accessions with ten RAPD primers revealed an average polymorphism of 24.99%. Also the Genotype Genotype*Environmental (GGE) biplot analysis which incorporates divergence effect due to the genotype (PC1) and the divergence effect due to interactions between the genotype and field parameters (PC2) was 44.7%, which is not statistically significant (PC1 + PC2 should be more than 70% for the divergence among accessions to be statistically significant). These indicate very low genetic diversity among the accessions used in the study, indicating narrow genetic diversity of J. curcas germplasm in the country. It is therefore recommended that our local germplasm of J. curcas should be officially conserved whiles immediate efforts should be made to widen the genetic base through research. This can be done through introduction of accessions from countries such as Mexico and Central America which are the centers of origin of the plant. Also genetic resources of the plant can be introduced from India where much research and improvement on the plant has already been done. Through Inter-specific hybridization breeding of imported accessions and our local accessions the local germplasm can be improved. This will provide good quality planting material to both farmers and individuals to boost the production of the plant in the country to meet the government’s aspiration of bio-diesel production from J. curcas seeds as an alternative source of fuel.

Source: KNUST