Genetic diversity analysis of wild germplasm and cultivated clones of Hevea brasiliensis Muell. Arg. by using microsatellite markers

Twelve microsatellite markers were used to detect DNA polymorphism among 108 accessions of #Hevea brasiliensis# inclusive of 40 cultivated (Wickham) clones and 68 wild accessions (1981 Amazonian accessions) collected from Amazon forest. In this study, the extent of genetic diversity among Wickham clones and wild accessions (1981 Amazonian accessions) in selecting suitable parents for enlarging genetic resource in Thailand's breeding program was evaluated. Genetic similarity values between genotypes calculated from all the microsatellite markers, were used to produce a dendrogram of the relationship among accessions, using the unweighted pair-groups method with arithmetic average. A total of 170 alleles were detected. The number of alleles ranged from 5 to 21, with an average of 14 alleles per marker. M574 marker demonstrated the highest polymorphism with 21 alleles, while M264 and M692 markers showed the lowest polymorphism with 5 alleles. The results clearly demonstrated that wild accessions were more polymorphic than cultivated Wickham clones and could be divided into three clusters, depending on the geographical origin of collection areas such as Acre, Rondonia and Mato Grosso state. However, two Rondonia accessions (RO/OP/4 20/16 and RO/A/7 25/133) could not be discriminated into the suitable cluster according to the high level of specific alleles. Despite the narrow genetic basis of Wickham clones, their high level of polymorphism could be detected. The result indicated that a relatively small number of microsatellite markers could be used as molecular markers for #H. brasiliensis# genetic studies. Furthermore, this information could also be used to help in guiding the selection of suitable populations for enlarging genetic resource in breeding schemes. (Résumé d'auteur)