Identification of high yielding genotypes of rubber (Hevea brasiliensis) at the early stage of their breeding cycle using rubber elongation factor (Ref) gene and promoter

Abstract

Hevea brasiliensis (Willd. ex A. Juss.) Muell. Arg. is the main species producing natural rubber, which is an important industrial raw material. Rubber Elongation Factor (Ref) is a major protein, which involves in rubber biosynthesis. Ref protein is highly homologous to the Ref gene. This research was conducted to analyse the nucleotide sequences of the Ref gene and Ref promoter of seven genotypes of year 2011 in a hand pollinated progeny (HP-42, HP-231, HP-202, HP-300- high-yielding, HP-19, HP-124 and HP-297 low-yielding), along with the selected five wild accessions (RO 22/63, MT 11-76-I, MT 11-76-II, MT 11-13 and MT 10-146) of H. brasiliensis to develop a molecular marker to early identification of highyielding genotypes. Already characterized, four H. brasiliensis clones (high-yielding and low-yielding Wickham genetic base) were used as controls for the analysis. PCR amplification of genomic DNA of all experimental materials resulted around 1250 bp fragment with Ref gene specific primer pair and around 700 bp fragment with both Ref promoterspecific primer pairs. No difference in base sequence was observed among high and low yielding clones, genotypes and wild accessions. Therefore, sequencing analysis of the Ref gene and Ref promoter showed the similar sequence in both low and high yielding clones. Sequence analysis should be carried out further for different regions of other genes of H. brasiliensis.