Development Of Introgression Lines Of Common Wild Rice (O.Rufipogon Griff.) From Jinghong In Yunnan Province And Fine Mapping A Set Of Complementary Genes For Hybrid Weakness

Rice is one of the most important crops in the world.It is important for both breeding and biological study to look for useful genes. Common wild rice (Oryza rufipogon Griff) is the progenitor of Cultivated Rice (Oryza sativa L.).Wild rice has adapted to weather and unfavorable environments under natural selection,carries abundant gene.It is very important to exploit and utilize favorable alleles of wild rice in rice breeding.In this study, an advanced backcross population, derived from a cross between Jinghong wild rice (O. rufipogon Griff.),as the donor and Teqing(indica cultivar),as the recurrent parent. In this process,we noticed several introgression lines with extremely weak growth phenotypes,genetic analysis and molecular mapping, hybrid weakness is identified by a set of dominance complementary genes (hwi-1/hwi-2). The main results were as followings.1. An advanced backcross and consecutive selfing strategy was used to develop introgression lines (ILs), which derived from an accession of Oryza rufipogon Griff, collected from Yuanjiang County,Yunnan Province of China,as the donor,and an elite indica cultivar Teqing (O. sativa L.), as the recipient. Finally,we developed A set of282introgression lines through marker-assisted selection(MAS).2. A set of282introgression lines representing97%of the genome of common wild rice(O.rufipogon Griff.) in genetic background of cultivated rice(O.sativa L.) were developed using212SSR markers.The genome in each introgression lines harbored chromosomal fragments of O.rufipogon ranging from1.5%to23.6%, with an overall average of18.8%.A total of3727substituted segments were detected in the set of282introgression lines,The length of introgressed segments ranged from0.1cM to80.8cM, with an average of25.5cM.3. In the process of the construction of introgression lines,we noticed several introgression lines (JIL015, JIL026,JIL031,JIL061, JIL062) with extremely weak growth phenotypes.Genetic analysis indicated that hybrid weakness controlling a set of dominant complementary gene (hwi-1/hwi-2).4. Fine mapping of hwi-1.1266individuals derived from introgression lines (JIL026)and Teqing backcross construction of near isogenic lines.Through substitution mapping method.hwi-1gene was localized to a78.5Kb region by two molecular markers InDel-3and MG17on chromosome11. In the region of13open reading frames, and each of the reading frame for function prediction.5. The hwi-2gene was narrowed down to a candidate genomic region of200Kb long defined by markers RM11787and RM5501on the chromosome1,by using the BC4F5plants developed from JIL102,which had the heterozygous segment between RM297and RM3304on the chromosome1and the introgressed segment between MG9与MG17on the chromosome11.