Mapping And Genetic Study On The Single Segment Substitution Late Rice Heading Stage Material

Rice is one of the most important food crops,and it is the staple food of more than half of the population in the world.Rice which has 389MB gene group is the minimum gene group crop in cereal crops.Japonica rice "Nipponbare" and indica"9311" had completed the whole genome sequencing work,for example,a high density of molecules linked marker map,gene annotation data information,etc.That provides powerful data resource support for rice disciplines of basic research and breeding work.Rice has the absolutely leading position in the scientific research of cereal crops.Like Arabidopsis,rice is the model plant in genetic science and genomics research of monocot.Chromosome segment substitution lines are the sub-groups of important value,which can be used as the carrier of important traits and create new traits in breeding work,could effectively exclude the impact from genetic background for the study of QTL mapping and cloning in rice basic research.In this study,the single egment substitution line(SSSL)was an typical late growth period material,which was screened from chromosome segment substitution lines of Nipponbare and 9311.The material was typically affected by photoperiod rhythm.In the short-day conditions,There was no significant difference between SSSLs and wild type 9311.But in the long-day conditions,SSSLs showed co-dominant phenomenon.The recessive mutant exhibited extremely late heading date,and the heterozygote has a little later than the normal 9311,This experiment made a lot of work focused on long-day conditions.By sowing 9311 by stage,gene map with extreme groups and the gene expression of related genes rhythm were investigated in long-day conditions.The main results were as follows:1 9311 was sowed by stage in long-day condition,plant height,spike length,grain weight,seed setting rate,leaf length,effective panicle,grain yield per plant and other key traits were observed.There were obvious differences on the strains high,spike length,grain weight,seed setting rate,leaf length and grain yield per plant between SSSL and 9311.The difference reached highly significant level on flag leaf length,grain weight,seed setting rate and spike length.2 According to the MAS technology and gene chip technology,we focus the Nipponbare fragment at 8.32Mb-20.375Mb area on the chromosome 6 which linkage with the SSR primer RM3.Building the F2 group of the SSSL material,whichever is the extreme later than heading individuals,we resolved the QTL to an 222-kb region between 116240 and 116500.3 Long-day treatment of SSSL and 9311 was carried out on the sixth day running from 8:00 to 22:00 pm in the artificial climate chamber.The key genes of the biological rhythm,Ehdl and Ghd7,emerged reducing and raising phenomenon,respectively.In the further study,the expression level of the unkown gene LOC_Os06g30820 and LOC_Os06g30830 were analyzed,and the difference between genetic background and genetic expression was observed.