Linkage analysis of rice by use of RFLPs (Restriction fragment length polymorphisms).

点击翻译按钮获取中文摘要

Restriction fragment length polymorphisms (RFLPs) represent differences in the length of the fragment of genomic DNA produced by digestion with specific restriction enzymes. They can be used as useful genetic markers in genetic analysis and breeding programs. In this study, linkage mapping was conducted on RFLP markers, morphological marker genes and isozyme loci in rice in collaboration with RFLP groups of National Institute of Agrobiological Resources and Hokuriku Agricultural Experiment Station, Ministry of Agriculture, Forestry and Fishery.RFLPs were detected using clones selected from a Pst I genomic library of rice as DNA probes by Southern analysis. Segregation data in a F_2 population (144plants) from a cross between Kasalath (Indica) and FL134 ( a multiple genetic marker line of Japonica) were analyzed by the maximum likelihood method. The linkage map constructed comprised possible twelve linkage groups of rice. It was possible to assign six of the twelve groups to their respective chromosomes (chromosomes 4, 5, 6, 8, 9 and 11 according to Nishimura's designation) based on the information on chromosomal location of morphological and isozyme markers. In order to assign the rest of the RFLP linkage groups to their respective chromosomes, we performed gene dosage analysis of hybrid primary trisomics and F_2 trisomic segregation analysis. With these analyses, we assigned 21 RFLP clones to specific chromosomes and verified relationship of twelve RFLP linkage groups with the respective chromosomes.We also detected the linkage among two bacterial blight resistance genes, Xa-1 and Xa-2, and two RFLP markers. The arrangement of the loci were lg-Ph-Xa-1-Xa-2-120-102 on chromosome 11. The comparisons of the RFLP and conventional linkage maps were also discussed in this study.