Mapping Of QTLs For Nitrate Nitrogen Utilization And Uptake Efficience,and Grain Weight In Rice Based On Chromosome Segment Substitution Lines(Oryza Sativa L.)

Rice is one of the most important food crops in China,and the cloning of QTLs for yieldrelated traits is a hot research topic,of which thousand grain weight and nitrogen use efficiency are important factors affecting yield.Chromosome fragment substitution lines as materials for genetic studies are advanced populations generated by high generation backcrossing compared to primary populations,so carrying few and small target fragments are excellent materials for QTL localization.In this experiment,a set of 112 chromosome fragment substitution lines were obtained from 8001 and Huazhan,which were rich in traits and genotypes.From these lines,KT2330 was selected to have a significant variation in grain weight compared with Huazhan,and the fragments carried by KT2330 were precisely identified by combining the resequencing results of the extreme plants and parents in the population.The main findings are as follows:1.KT2330,was identified from 112 chromosome substitution lines with 8001 as donor and Huazhan as recipient and showed a significant difference in grain weight from the parent Huazhan,showing a significant increase in thousand grain weight,as well as a significant increase in plant height and width.2.A total of eight pairs of markers linked to the thousand grain weight trait were obtained by resequencing analysis of cryptic markers near the chromosome 7 linked RM3555 marker.Marker scans of the 2021 and 2022 segregating populations placed the thousand grain weight associated QTL(qTGW7).Initially located between marker S7-36-VG0727634,the physical location was between 25.10Mb-27.63Mb with a size of 2.53Mb.3.Two parents(Huazhan and 8001)were treated with 112 chromosome fragment substitution lines with potassium chlorate solution to examine the nitrate-nitrogen use efficiency index CR%(seedling length after potassium chlorate treatment/water treatment),and QTL analysis was carried out using IciMapping software in combination with molecular markers.This thesis contributes research material to the fine targeting of genes for grain weight and nitrogen fertilizer use efficiency,and provides a basis for the screening of superior haplotypes in natural populations to exploit their potential value for production.