Construction of RFLP and AFLP Genetic Linkage Maps For Oil Palm (Elaeis Guineensis Jacq.) Using a Deli Dura X Yangambi Pisifera Cross
Chua, Kia Ling (2006) Construction of RFLP and AFLP Genetic Linkage Maps For Oil Palm (Elaeis Guineensis Jacq.) Using a Deli Dura X Yangambi Pisifera Cross. Masters thesis, Universiti Putra Malaysia.
Conventional oil palm improvement using traditional breeding is a slow and expensive process. If markers linked to a useful trait, such as yield, shell thickness and embryogenesis rate, can be identified, marker-assisted selection (MAS) can be carried out, which can reduce the time taken for conventional breeding. Generating a linkage map is the first step towards marker-assisted selection. In this study, two oil palm maps were generated based on 87 F1 progeny of a controlled cross (Deli dura x Yangambi pisifera). A total of 106 RFLP markers and 171 AFLP markers were identified and scored. Of the 277 markers scored, 28 markers (10.1%) were deviated from expected Mendelian ratio (p<0.05). Pseudo-testcross strategy was used to generate two parental maps. The dura map consisted of 18 linkage groups and covered a total map distance of 584.1cM. The pisifera map resolved into 19 linkage groups and covered a total map distance of 1099.3cM. Of all the markers analyzed, 16.9% of the dura markers and 25.1% of the pisifera markers remained unlinked. RFLP marker although difficult to develop, proved very useful because only a small fraction is deviated from the expected Mendelian ratio. Furthermore, about 80% of the RFLP markers can be mapped on both parental maps. More markers will be needed to reduce the number of linkage groups of both parental maps to the haploid chromosome number of oil palm (n=16). Five homologous regions between the dura and the pisifera maps were identified by comparing the co-dominant RFLP markers. The orders of the homologous markers were conserved and the overall distances were nearly the same in both varieties, although a small difference was observed in one homologous region on linkage group D3 and P5. This difference might be due to unequal recombinations that occurred at that particular region.
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