Evaluation and utilization of the Hevea germplasm collected from 1981 IRRDB expedition to the Amazon; a review

Rubber industry in Sri Lanka that extends approximately around 133,000 ha, is largely based on Wickham’s genetic base. Use of genetically improved high yielding planting materials is perhaps the only and cheapest way to increase the yield per unit area. However, due to directional selection carried during past Hevea breeding, the genetic diversity in the Hevea breeding pool has started to narrow down. Non Wickham’s genetic collections can provide genetic diversity and possible desirable genes for plant breeders to overcome this situation. Currently around 8000 accessions of Hevea germplasm have been collected and conserved in Sri Lanka. Majority of them came from the collection of 1981 International Rubber Research Development Board expedition in the Amazonian habitats. The characterization and evaluation of this germplasm was started in early 1990’s and continue until today. Two direct selections to the RRISL clone recommendation has been made in 1994 as GPS I and GPS II. Large number of accessions were used in nearly nine hand pollination programmes carried since 1995 and resulted in development of around 1075 new genotypes which now in various evaluation steps. Ten selected genotypes from 1995 hand pollination programme are now in the advanced stage of evaluation, before the recommendation. The process of characterization, evaluation and maintenance of ex–situ germplasm collection with a wide range of genetic materials for useful trials is in progress.