RUBBER ELONGATION FACTOR (REF) AND SMALL RUBBER PARTICLE PROTEIN (SRPP) GENE EXPRESSION RESPONSES TO VARIATION OF SEASONAL CHANGE IN FOUR SELECTED RUBBER CLONES

Abstract

Applying molecular marker for estimating the amount of production yield will help to reduce time for selecting rubber clones. In this study, gene expression analyses under different seasons were performed in rubber tree since seasonal change is one of the most important factors to latex yield. Four rubber clones (SK1, NK1, T2 and SK3) that have high latex yield potential were used in this study. The latex yields and gene expression levels of REF and SRPP genes were compared over two year, using RRIM 600 clones in the same fields as their paired controls. Moreover, the seasonal effects on gene expression were analyzed. The average yields and gene expression were obtained from 13 years old mature trees in the early rainy season, the late rainy season and the summer season. This study revealed that all four selected clones gave higher production yield and exhibited superior REF and SRPP gene expressions than compared-control RRIM 600. Gene expressions of REF and SRPP had positive relationships with latex yield. Moreover, we found that the highest REF and SRPP gene expressions were recorded in late rainy season that agreed with the amount of production yield. The late rainy season was a good period to investigate differential expression of the candidate molecular marker genes. The results corroborate the two genes’ expression as surrogate selection criteria for high yield rubber clones