Genetic Diversity and Phylogenetic Evolution Among 1981'IRRDB Wild Germplasm and Cultivars Using ITS Markers in Rubber Tree
Using internal transcribed spacer(ITS) mark technology, 44 rubber trees including 37 wild germplasm of 1981'IRRDB and 7 cultivars were used to investigate the genetic diversity and phylogenetic evolution. Nine wild germplasms and one cultivar presented heterozygosis of ITS sequence. The sequence length was 583-588 bp,and the G+C content was 65.52%-67.17%. There were 87 variable sites in the ITS sequence, and the nucleotide diversity of ITS2(0.014 33) was higher than that of ITS1(0.010 10) and 5.8 S(0.010 31), showing that ITS2 was a more suitable choice for genetic diversity and phylogenetic evolution. Haplotype analysis showed that H8 was an older and more frequent haplotype, and located in the center of the network graph. Five cultivars and parts of the wild germplasms from Rodo^nia had similar genetic background, and cultivars included Reyan7-20-59, RRIM600,Reyan 7-33-97, Reken 628 and Reyan 88-13. In addition, neutral test and network of haplotype implied that the trees had gone through an event of population expansion.