QTL Mapping About Dwarfing Character Of Maize Male Sterile Mutant Obtained From Space Flight

Maize is one of the most important crops(rice,corn,wheat)in the world,it is also one of the most widely planted in the world.The contribution rate of maize to grain production is obviously higher than rice and wheat in China.So improve the yield of maize is an important step to protect China's food security.Useing the male sterile lines of maize not only save the complex artificial labor,but also improve the seed purity.With the urbanization of labor force,the popularity of use the male sterile lines is imminent.Therefore,we need to accelerate the pace of the male sterility of maize research and sterile seed production.In 1996,the Maize Research Institute of Sichuan Agricultural Uniersity bring chuandan9 seeds to space by recoverable satellite.A male sterile mutant was obtained when plant the chuandan9 seeds.The male sterile mutant pollen was completely aborted and the sterility was stable,through the reaserch of mutant was found that the sterility was controlled by a pair of recessive single genes,and the sterile gene was located on the bin3.08 locus by SSR molecular marker in chromosome 3.Through many years of observation of sterile plants is often accompanied by the dwarf,the majority of male sterile plants higher than fertile plants.In view of the phenomenon of dwarfing male sterile plants,this paper constructed five populations to QTL mapping of plant height and analysis the reason of dwarf,explaining the reason at the molecular level.This paper using the male sterile mutant construct five population.The male sterile mutant were multiplied by sister cross in many years,the sterile(A1?A2?A3)plants of the same generation were obtained in the segregating population,A1 and A2(female parent)were used to cross with inbred lines B73 and Mo 17,respectively.Using inbred line B73 as recurrent parent and A3 construct(A3×B73)BC2F2 backcross population.An cross sister F2 population was constructed from a heterozygous inbred in the cross sister population.(A1 ×B73)F3 population were constructed by self crossing of 9 key exchange individuals in(A1×B73)F2 population.The results is that:1.As the preliminary study of this research,we locate the sterile gene to bin3.08 site of maize,so we take QTL mapping of 22 traits with the chromosome 3,including plant height,ear height,tassel length,tassel branch number,leaf shape and so on with the five populations.Detect the plant height QTL in the vicinity of the sterile gene.The results showed that male sterile gene positioning region locate a major piant height QTL in the five populations,the phenotype contribution rate between 10.14-45.31%,other related QTLs are mapped near the sterile gene region.2.1n order to find out whether other chromosomes also have plant height QTLs,whether the QTLs will interact each other.Therefor,through the(A1×B73)F2 population QTL mapping of plant height with all chromosomes.We focused on whether the other chromosomes had plant height QTL and analyzed the relationships between these QTLs.The plant height QTL was found in the male sterile gene near the same positioning,the phenotype contribution rate was 26.96%.At the same time,some QTLs associated with plant type traits were located in the vicinity of sterile genes.These conclusions were consistent with the results of QTL mapping of the chromosome 3.Meanwhile,the QTLs of plant height were mapped on chromosome 1?4?10,the contribution rates were 9.54%,7.05%and 6.35%,respectively,those belong to the micro-strain QTL.3.Through the plant height QTL mapping in chromosome 3 and all chromosome with five population,it is shown that there is indeed a site that strongly affects plant height in the vicinity of the sterile gene.Combined with the phenomenon of "high sterile line" and "dwarf fertile plant" observed in the field for many years,it is concluded that the sterile gene is linked to a dwarfing gene,which leads to the dwarfing of sterile strain.Through the pollination and conservation of "high sterile lines",the plant genotypes were preserved for reaserch the fertility and plant height genes.At the same time,the A1 × B73 and A2 × Mo 17 groups were used to construct the(HIFs)and BCn + 1F1 backcross families(B73 and Mo17 as reincarnation parents,respectively)for the study of dwarfing and cloning of the plant height QTL.