Linkage Map Construction and Genetic Recombination Analysis of a Rice Recombinant Inbred Line Population
Date Issued
2008
Date
2008
Author(s)
Li, Wen-Ya
Abstract
A molecular linkage map of rice was constructed using 128 recombinant inbred lines (RILs) from an inter-subspecific cross between cultivars Taichung-Sen 10 (TCS10) and Koshihikari (KOSH). It consists of 80 SSR (Intra-SSR) DNA markers distributed in 12 linkage groups, totally spanning 1475.4 cM with an average interval spacing 18.44 cM. This is the first RIL linkage map of rice in Taiwan, and it is a powerful tool for marker-assisted selection and genetic recombination studies.ince the SSR DNA markers have codominant inheritance, it makes study genetic recombination of the RIL individuals become possible. According the genotypic frequencies of SSR markers, segregation distortion was found in the RIL population. About 58.75％ of investigated markers, 47 out of 80, were segregated distortedly from Medelian ratios (31:2:31 or 33:31). Significant distortion segregation is often found in the marker loci of chromosomes 2, 6, and 9, and seldom found in the chromosomes 1, 8, and 12. The averaged recombination frequency was 2.37 times per pair of chromosomes. The chromosomes 12 and 3 respectively had the highest (4.19 times) and the lowest (1.3 times) frequencies of recombination in the RIL population. Compared to japonica type parent (Koshihikari), indica type parent (Taichung-Sen 10) contributed more genetic materials in the chromosomes 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, and 12, to the RIL population, but less in the chromosome 7. The averaged homozygosity (94.6％) was deviated from the expected ratio 96.9％. The marker loci of chromosomes 6 and 2 respectively had the highest (98％) and the lowest (90％) homozygosity ratio in the RIL population. There were 16 alleles segregating in the RIL population but not detected in both parents. The sequence variations at the simple repeats or the flanking regions were detected. Our results have revealed that segregation distortion to indica genetic background and relatively high levels of heterozygosity are often found in the RIL population.his study has developed the first rice RIL population and constructed the linkage map. It is a useful tool for genetic analysis of important traits and progeny selection of cross breeding.
Subjects
rice
RIL
molecular marker
linkage map
genetic recombination
segregation distortion
Type
thesis
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