| Wheat is a main food crop in China,and its output per unit area has been steadily increasing year by year.Along with the increase of people’s living standards,the quality of wheat has been paid more and more attention.The selection of high-quality wheat varieties has become an important breeding target.The main quality traits of wheat include grain hardness,protein content,silty parameters,starch paste properties and so on.Among them,starch paste properties are the most important traits for measuring wheat quality.Starch paste properties not only reflect the characteristics of the material basis such as starch components,but also play an important role in food quality such as Chinese steamed bread.Therefore,paste properties can be used as an important indicators for screening of offspring in the process of wheat breeding prograsms.In this study,a set of recombinant inbred lines（RILs,184 lines）derived from the cross‘Tainong 18 × Linmai 6’（TL-RILs）were used as the test materials.Three years of field trials were conducted.The harvest geains were milled and determined six paste properties,peak viscosity（PV）,trough viscosity（TV）,final viscosity（FV）,breakdown（BD）,setback（SB）and falling number（FN）.Combining with genetic map based on unigenes constructed by our laboratory,QTL analysis was carried out for wheat starch paste properties.The objective is to provide the foundation for molecular marker-assisted breeding in wheat breeding prograsms.The main results are as follows:（1）Phenotypic variation analysis showed that the six paste propertie traits were obviously different between the two parents.For RILs,a large range of variations were showed under three environments.The largest coefficient of variation（CV）was BD in E3environment（21.48%）;and the smallest was SB in E1 environment（6.03%）.The minimum heritability is 48.64%（SB）and the maximum is 63.15%（BD）.The transgressive inheritance was found for all the six traits.Analysis of variance（ANONA）showed that the variances of the six traits were all significant at p≤0.001 level both for genotypes and environments.The correlations between traits were mostly significant at p ≤ 0.01 level.（2）QTL analysis showed that a total of 171 QTLs（190 QTLs for trait-environment combination）were detected on 19 chromosomes except for 4D and 7B.Among them,a number of 78 QTLs were positive,indicating that the increased effects of QTLs were comefrom Tainon 18;whereas 93 QTLs were negative,indicating that the increased effects were derived from Linmai 6.A single QTL can account for 1.06%-20.90% of phenotypic variation.The maximum LOD was 50.05（FV）.（3）A number of 16 QTLs ware high frequency expression QTLs（RHF-QTL）or stable QTLs,which detected in two or more environments.Of which,three RHF-QTLs（QPv-4B.1,QTv-6D.3,QFv-7A.1）were detected in all three environments;and 13 RHF-QTLs（QFn-1A.1 、QFn-2B.2 、QFv-4B.1 、 QSd-4B.2 、QFn-5D.1 、QBd-5D.4 、QBd-6B.5 、QSd-6D.1、QFv-6D.4、QFn-7A.1、QBd-7A.2、QTv-7A.1、QBd-7A.3）were detected in two environments.（4）We define a QTL cluster is that the RHF-QTL of two or more traits can be found on the overlapping confidence intervals.Two clusters（C1 and C2）were obtained on the 4B and 6D chromosomes involving 4 RHF-QTLs.The markes covered by clusters,S051442 S051446 and S091800 S091804.1,could be used in molecular marker-assisted breeding of starch gelatinization properties.C1 was located on chromosome 4B includes two RHF-QTLs（QPv-4B.1,QFv-4B.1）with an average of 9.22%-11.63% of phenotypic variation.C2 was located on the 6D includes two RHF-QTLs（QTv-6D.3,QFv-6D.4）with an average phenotypic variation of 13.18%-13.94%.The increased effects of QTLs for both cluster were come from Linmai 6. |
