Using Indica-japonica Chromosome Segment Substitution Lines To Map QTL For Pollen Smei-sterility And To Construction A Subset Of CSSLs For Chromosome 3 In Rice

Chromosome segment substitution Lines(CSSLs) are ideal tools for facilitate genetic analysis of complex traits in rice.CSSLs can be used to detect beneficial genes,to develop a set of novel stocks for fine mapping or cloning of QTLs.Additionally,lines with desirable genes can be directly use in rice breeding.In this work,a set of chromosome segment substitution lines that Indica variety zhenshan97B as recurrent parent and japonica variety Nippobare as donor parent,were used to map QTL for pollen semi-sterile in rice,and to construction a subset of chromosome segment substitution lines for chromosome 3 in rice.The main results are as follows:1.A line(IL37) with semi-sterility was selected from a set of chromosomal segment substitution lines,of which each contains a single or few substitution segments of a japonica variety Nipponbare in the genetic background of indica variety Zhenshan97B. The graphical genotype analysis of the line(IL37) by using 160 polymorphic SSR revealed that it harbors only 3 chromosomal segments from the japonica with the simliar genetic background to Zhenshan97B.Its derivative F₂ and F₃ segregation populations were planted in Wuhan and Hainan respectively for detection of quantitative trait loci (QTL) of pollen fertility and spikelet fertility via single-marker analysis and interval mapping.A novel QTL of pollen sterility was detected at the interval RM262-RM475 on chromosome 2,accounting for the phenotypic variation of 13.9%.The results suggest that japonica substitution segment carrying the QTL is one major cause of the semi-sterility in IL37.Further fine mapping and identification of candidate gene in the QTL region will facilitate us better understanding of the genetic basis of pollen sterility in rice.2.After 1 backcrossing and 3 selfing of indica-japonica substitution lines of BC₆F₂ generation,together with MAS during the advancement of generations,we obtained a subset of chromosome segment substitution lines consisting of 35 individuals about chromosome 3.It haboured 48 introgression segments from Nippobare,and coveraged the entire chromosome 3.Among 48 introgressed segments,the longest segment is 64.5cM, the shortest one is 1.4cM,the mean length of segments is 15.8cM.Using the subset of CSSLs,18 QTLs of 8 agronomic traits were detected in 2007 and 2008.3 QTLs associated with plant height,3 QTLs for heading date,1 QTL associated with the width of flag leaf,1 QTL related to panicle length,1 QTLs for filled grains per plant,3 QTLs associated with grain length,2 and 4 QTLs found related with grain width and 1000-grain weight.Of those,7 QTLs(qLW3-1,qPL3-1,qGW3-3, qGL3-1,qGL3-2,qGL3-3,qgw3-2) associated with the width of flag leaf,panicle length, 1000-grain weight,grain length and grain width are novel QTLs.