QTL(Quantitative trait locus) can be divided into several simple Mendelian factors using SSILs(Single segment introgression lines) with the characterizations of single introgressed segment, purifying of genetic background, genetic stability and so on.

Chromosome introgression lines(CILs),also namely chromosome segment substitution lines,and backcross recombinant inbred lines,are usually developed by conventional backcrossing and selling with the aids of MAS approaches,which one or a couple of small chromosomal segments from the donor are introgressed into the genome of receptor.

A set of chromosome segment substitution lines (CSSLs),derived from Asominori/IR24 with Asominori as the recurrent parent,was planted and phenotyped for grain length (GL),grain width (GW) and length-width ratio (LWR) of milled rice in two successive years and four sites.

Using an indica variety 93-11,a japonica variety Nipponbare and seven chromosome segment substitution lines(CSSLs)with a genetic background of 93-11 introgressed from Nipponbare as the materials,we investigated seed shattering with 153 simple sequence repeat(SSR)markers on rice chromosomes,the introgressed segment and the quantitative trait loci(QTL)for seed shattering.

In the paper,with an indica variety 93-11,a japonica variety Nipponbare and 8 chromosome segment substitution lines(CSSLs) with the genetic background of 93-11 introgressed from Nipponbare as the materials,using 153 SSR markers distributed on 12 rice chromosomes,the substituted segment and the QTLs for grain shape were analyzed.