Construction And Characterization Of Contiguous Introgression Lines In Genetic Background Of Elite Restore Line 9311

In this study, we have constructed a set of introgression lines (ILs) carrying japonica variety Nippobare segments in the uniform genetic background of an indica variety 9311 through backcross program and molecular marker-aided selection (MAS). There are no differences between ILs except each containing only one or small japonica segment. The QTL analysis will be more powerful as using the ILs population to some extent with reducing the effect of heterogeneous genetic background. Our objective is to characterize genetic effect of the introgression segments, to detect beneficial genes, to develop a set of novel stocks for fine mapping or cloning of QTLs and to use some lines with desirable genes directly in rice breeding. The main results as follows:Indica variety 9311 as recurrent parent and japonica variety Nippobare as donor parent were used in the backcrossing program. After 4 times backcrossing and 3 selling and selection with MAS during the advancement of generations, we obtained a contiguous introgression population consisting of 125 individuals. All the ILs habouring 174 introgression segments from Nippobare have the genome proportion of the recurrent parent ranging from 93.8% to 99.9%, with an average of 98.4% and the mean length of segments is 21 cM. There exist various numbers of introgressed segments among the 12 chromosomes; Among 174 introgressed segments, the maximal number of 20 introgressed segments located on chromosome 1, while only 9 introgressed segments existed on chromosome 9 and 10.Ninty-seven TLs were detected for 13 agronomic traits using the contiguous ntrogression lines. Of those, QTLs associated with plant height, 9 QTLs for most internode length, 8 QTLs or econd internode length, 25 QTLs associated with tillers per plant, 3 QTLs associated with heading date, 39 and 48 QTLs found related with flag leaf length and width; 4 QTLs associated with panicle weight, 43 QTLs associated with panicle length, 5 QTLs associated with seed setting, 15 QTLs associated with panicle bald. 33 QTLs and 7 QTLs revealed for grain length and width. There are 37, 25, 22, 23, 23, 22, 33, 9, 19, 22, 18 and 6 QTLs on chromosome 1 to 12 respectively. 3 QTLs (Ph-1-2, Ph-3-1, Fll-5-1) associated with plant height, heading date and seed setting are new QTLs.