QTL Mapping For Grain Filling Rate In Wheat(Triticum Aestivum L.) And Molecular Markers Development For Thousand Kernel Weight

Wheat（Triticum aestivum L.）is one of the most important food crops in our country,its yield and quality has been the focus of wheat breeders.Grain filling rate is the key period of wheat yield formation,and the duration of grouting and grain filling rate directly affect grain size,grain weight and final yield.Therefore,it is very important to study the correlation between grain filling rate and yield related traits.In the present study,linkage analysis and association analysis based on high density genetic map for grain filling rate and thousand kernel weight were studied using a recombinant inbred line（RIL）consisting of 173 lines derived from a“Shannong01-35×Gaocheng9411”cross and a natural population consisting of205 wheat varieties.In addition,a new CAPS marker was developed in QTKW4 B.4-17 target segment using bioinformatics method,which could be used for fine mapping.The mainly results of the study were as follows:（1）Important genetic loci for kernel weight related traits: linkage analysis detected the QTL controlling kernel traits mainly distributed on the 4B and 5B chromosomes.Of them,QKL/W4 B.3-9 QKL4 B.4-17,QKW4 B.3-9,QKW4 B.4-17,QKT4 B.4-3,QKT4 B.4-17,QTKW4 B.4-17,QKD4 B.4-13,QKD4 B.4-17 and QKD5 B.5-445 were the main QTL affected kernel traits,its genetic contribution rate were greater than 10%.In addition,in the correlation analysis,the main associated loci for kernel weight related traits were detected in the chromosome 2D（Kukri_c13329₈00）.（2）Important genetic loci for grain filling traits: The linkage analysis detected that the QTL loci for grain filling rate and related traits were concentrated on the chromosomes 1B,4B,5A and 5B.Q（GFR1）4B.4-17,Q（GFR2）4B.4-17,Q（GFR2）4B.4-13,Q（GFR3）4B.4-13,QGFRmax4 B.4-17,QGFRmean4 B.4-13,QTmax4 B.4-13,QTKW1 B.8-70,QTKW5 A.10-6,QTKW4 B.4-17 is the main QTL for grain filling rate.The main effect correlation loci detected in the correlation analysis were Kukri_c35659₂50（5A）,BS00039185₅1（2B）,Excalibur_c29255₃66（4B）.（3）Molecular marker development and fine mapping: According to the sequence information of SNP marker RAC875_C27536₆11 and EX_C101685₇05,it was be used tofind the wheat gene sequence information by URGI and get the EST sequence fragment.Then,the EST fragments in the sequence were selected to develop4B-EST5 with restriction enzyme HaeIII as the tool.The result was tested by the RIL population and natural population.4B-EST5 is with the molecular markers of wheat grain weight can be applied in marker-assisted selection and genetic breeding,the genetic distance from 4B-EST5 between Rht-B1-TaTKW-4B,is apart from the Rht-B1 genetic distance of 1.1 cM,the distance from TaTKW-4B is 0.7 cM.The main effects and stable QTL provided a theoretical basis for marker-assisted selection breeding of wheat grain filling rate and grain weight related traits,and the new markers laid the foundation for the fine localization and mining of grain weight functional genes in the target region.