Genetic diversity is indispensable to sustain genetic gain in breeding programs. Cultivated sugarcane is a highly heterozygous hybrid derived from crossing two highly heterozygous parents. Sugarcane breeders traditionally rely on pedigree records to select parents. Molecular markers now make it possible to assess genetic diversity at the DNA level. Sixty three sugarcane clones were characterised using Target Region Amplification Polymorphism (TRAP) markers and pedigree relationship (Coefficient of parentage (COP)). The TRAP is a PCR-based marker with a fixed primer designed from Expressed Sequence Tag (EST) sequences paired with an arbitrary primer. It is supposed to unravel trait based polymorphism in the intronic- or exonic-regions of the genome. Ten genes evidently involved in sucrose accumulation (SUC), cold tolerance (CT) and trichome development (TRICH) were paired with four arbitrary primers. A total of 3,170 bands were scored of which 2,684 (85%) were polymorphic. Cluster and Multi Dimensional Scaling (MDS) analyses revealed a very narrow genetic diversity among the entries with genetic similarity (GS) ranging from 78 to 94%. Parentage did not seem to contribute to the grouping pattern in either the overall or individual gene family (SUC, CT and TRICH) clusters which was confirmed by the lack of correlation (r = -0.008) between the TRAP and COP-derived GS matrices. The complex genome of sugarcane and the strict assumptions inherent with estimating COP may account for this disparity. Analysis of Molecular Variance (AMOVA) revealed no structure in the population with regards to era of release (Pre- versus post-1980) with among clones accounting for up to 99% of the total variation and only 1% of variation attributable to era of release. Mixed Model Analysis on the MDS axes generally revealed no significant differences among era of release. Thus, pedigree records can enhance interpretation of marker-derived information especially in an interspecific crop like sugarcane where ancestral species possess and contribute different characteristics. Results from this study needs to be supplemented with sequence analysis of TRAP fragments to definitively relate the derived information to trait variation.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-01202005-134859 |
| Date | 21 January 2005 |
| Creators | Arro, Jie Alojado |
| Contributors | Collins Kimbeng, Kenneth Gravois, Prasanta Subudhi |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-01202005-134859/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.0061 seconds