Applications Of Genomics To Acacia Mangium Plus Trees (Superbulk) And Acacia Hybrid Tree Improvement For Wood Quality

• Main Authors: Ho Wei, Seng, Ismail, Jusoh, Hafizah, Abdul Razak., Angela Tida, Henry Ganie, Wickneswari, Ratnam
• Format: Proceeding
• Published: ResearchGate 2010
• Subjects: GE Environmental Sciences
• Online Access: http://ir.unimas.my/id/eprint/10041/; http://www.researchgate.net/publication/280141113

Acacia mangium superbulk and Acacia hybrid genetics and genomics studies are getting much attention because of its economical and ecological importance as well as scientific interest. Genomic information including genome sequence and expressed sequence tags (ESTs) is essential to understand the genes that control traits that are relevant to breeding and tree improvement programmes. The objectives of this study were to (a) determine the genetic diversity of Acacia mangium superbulk using expressed sequence tag derived short sequence repeat (EST-SSR) markers, and (b) analyse polymorphism of gene (i.e. cellulose synthase) related to wood density of Acacia spp using Cleaved Amplified Polymorphic sequence (CAPS). EST-SSRs are embedded in functional gene sequences and the markers may lead to the identification of genes controlling these traits [4]. Although EST-SSR markers are less polymorphic than genomic SSR markers, they are more useful in the assessment of functional diversity and comparative mapping while genomic SSRs are superior for fingerprinting and variety identification studies (Varshney et al., 2005). In the present study, 93 fresh young leaf samples were collected from 3 different areas, namely Similajau (Borneo Tree Seeds Seedlings Supply Sdn Bhd.-BTSSSB), Bintulu (DAIKEN) and Kota Samarahan (UNIMAS arboretum) and 13 EST-SSR markers were chosen for determining the genetic diversity of A. mangium superbulk. Total genomic DNA was isolated from fresh leaves of A. mangium superbulk using a modified CTAB method. Fragment analysis was conducted by using ABI PRISM® 3100 Genetic Analyzer and Genemapper™ Version 4.0 software (Applied Biosystems, USA). The genotype data was then analysed using PowerMarker software to determine the genetic diversity of A. mangium superbulk. A. mangium superbulk collected from BTSSSB showed the highest level of genetic diversity (N = 40; He = 0.474; PIC = 0.432) compared to Daiken (N = 40; He = 0.458; PIC = 0.429) and UNIMAS Arboretum N = 13; He = 0.364; PIC = 0.333) with an average of 0.432 and 0.398 for He and PIC, respectively detected in the present study. This result was comparable to the genetic diversity estimated for 11 populations of A. mangium in Pacific regions with the mean expected heterozygosity (He) of 0.081 as revealed by using isozyme markers [6]. A. mangium superbulk is the improved material or second generation of A. mangium whose properties and characters have been improved through many years of selected planting by BTSSSB in Similajau, Sarawak. The original seed sources were obtained from the CSIRO first generation seedlings and seed orchards of A. mangium in North Queensland.