Construction Of Chromosome Segment Substitution Lines And Mapping Of Shattering QTLs In Common Wild Rice (Oryza Rufipogon Griff.).

Common wild rice（Oryza rufipogon Griff.）forms many characteristics significantly different from those of cultivated rice（Oryza sativa L.）under complicated environment in its evlution process and rich genetic diversity.These potentially beneficial characteristics in the wild rice are important resources for improvement of cultivated rice varieties.However,most of these beneficial traits in common wild rice are quantitative traits.The genetic background of primary mapping population（F₂,RILs,DH,etc.）is so complex that it is impossible to accurately identify the location,effect and interaction of individual quantitative trait locus.Whereas each chromosome segment substitution line（CSSL）has a recurrent parent genetic background except for one or a few substitution segments from donor parent.As the CSSLs can simplify their genetic background and be used to dissect complicated genetic character into single Mendel factors,therefor,the CSSLs have become one of the important mapping populations for analysis of quantitative trait loci（QTLs）.In order to transfer beneficial genes from wild relatives by distant hybridization.In this study,a set of chromosome segment substitution lines derived from a cultivar,93-11,as recipient crossed with an accession of common wild rice,DP30,as donor was constructed by backcross,selfing and marker-assisted selection（MAS）.A complete set of genome-wide chromosome segment substitution line population（DP30-CSSLs）of common wild rice core collection DP30 was constructed and used to investigate the phenotype of 17characters and analyze and map the shattering trait QTLs.The main research results are as follows:（1）Based on high-throughput sequencing of the 93-11 and DP30,285 pairs of InDel markers were developed with an average distance of 1.23 Mb for genomic analysis in process of CSSL construction.（2）The DP30-CSSLs constructed contained 132 lines,and the totle length of all target substituted segments was 536.4 Mb.The coverage rate of all target substituted segments to the DP30 genome is about 91.4%.Among them,99 lines were single substitution segment lines（SSSLs）,each of which contained single substitution segment from DP30.The toale length of substitution segments of the 99 SSSL was 359.66 Mb with coverage rate of 61.36%of DP30 genome.（3）DP30-CSSLs was used to investigate the phenotype of 17 traits,and 40quantitative trait locis（QTLs）and 6 qualitative trait genes were detected.Among them,14 alleles have been cloned,while others may be new genes.（4）There were 9 CSSLs with shattering under control by 4 QTLs.In order to carry out linkage analysis of shattering QTL qSH11.1 with large genetic contribution,a chromosome single segment substitution line（RZ8）with relatively simple genetic background was selected to construct a secondary F₂mapping population by cross with 93-11.The qSH11.1 was final mapped to an about 1.5 Mb regions between InDel markers M5 and M6 on chromosome 11.This qSH11.1 locus is a newly discovered shattering QTL locus as there was no shattering gene report before in the near region.DP30-CSSLs constructed in this study are valuable materials for searching and identifying new QTLs from whole genome of the wild rice,and the finding of new QTL qSH11.1 will lay solid foundation for exploitation,fine mapping and cloning of shattering related genes.