Abstract: ObjectiveThe sources and formation pathway of 2n gametes which formed triploid rubber trees Yunyan 77-2 and Yunyan 77-4 were studied to provide reference for hybridization breeding of polyploid new varieties using natu-ral 2n gametes.MethodTriploid rubber trees Yunyan 77-2,Yunyan 77-4 and their parents were used as test materials. The sources and formation pathway of 2n gametes were identified by SSR markers,and heterozygosity of transfer parents of 2n gametes were analyzed.ResultSources of 2n gametes which formed Yunyan 77-2 and Yunyan 77-4 derived from female parent GT1 were identified by four loci respectively,while there was no locus which determined that 2n gametes derived from male parent PR107.Eight loci determined that the formation pathway of 2n gametes which formed Yunyan 77-2 was the first division restitution(FDR),two loci determined that the formation pathway of 2n gametes which formed Yunyan 77-2 was second division restitution(SDR).The probability of 2n gamete forming Yunyan 77-2 through FDR was 80.00%.Eight loci determined that the formation pathway of 2n gametes which formed Yunyan 77-4 was FDR,three loci determined that the formation pathway was SDR,the probability of 2n gamete forming Yunyan 77-4 through FDR was 72.73%.The 2n gametes which formed Yunyan 77-2 and Yunyan 77-4 transferred 60% and 70% heterozygosity of the pa-rents respectively.ConclusionThe 2n gametes which form Yunyan 77-2 and Yunyan 77-4 all originate from the female parent GT1,and the formation pathway of 2n gametes is FDR.