| Improvement of industry quality is one of the major wheat breeding objectives in China, and prediction of end-use quality on parameters determined by simple testing instrument as Mixograph is critical for efficient selection in breeding programes for wheat (Triticum aestivum L.) quality. The objects of this paper, which includes three parts, were to find some reliable, simple and easy Mixograph parameters to predict end-use quality, and to analyze the efficiency of marker of 5+10 glutenin subunit in quality wheat inprovement program in north China winter wheat region, to provide information for breeding for quality wheat in early generation selection.1.Two hundred and forty one cultivars and advanced lines were sown in Beijing, Jinan, Anyang, and Zhengzhou, China in 2002-2009 seasons. The Mixograph parameters were measured for determining their associations with Farinograph, Extensograph, and bread-making quality traits. Multiple stepwise regression analysis revealed that Farinograph stability time, Extensograph maximum resistance and energy area, and bread score could be efficiently predicted by Mixograph midline peak value, peak width, peak integral, time x value, and tail value, which accounted for 61.0-68.0% of the phenotypic variation, with the fitting degrees of 0.83 and 0.95 for the model for Farinograph stability time and Extensograph energy area, respectively. Farinograph water absorption and development time, Extensograph extensibility, and loaf volume could be predicted by Mixograph midline peak value, peak width, peak integral, right value, right integral, and time x integral, accounting for 46.0-55.0% of the phenotypic variance. The Midline peak integral presented as the most important parameter for predicting Extensograph maximum resistance and energy area, and explained 58.7% and 59.7% of the phenotypic variances, respectively. Midline peak integral and peak value were the two most important parameters when using Mixograph for quality testing.2.A total of 421 cultivars and advanced lines were sown at Beijing, Jinan, and Anyang in 2008-2009 season. Kernel hardness, flour protein content, and major Mixograph parameters including peak time, peak value, and peak integral were measured, and glutenin subunits were determined for investigating their associations. The results indicated that the combination of 1Ax1, 1Bx7+1By8 or 1Bx7+1By9, 1Dx2+1Dy12, Glu-A3c and Glu-B3j were dominant in the north China winter wheat region. The major Mixograph parameters were mainly influenced by additive effects of HMW-GS, together with LMW-GS, and some minor contributions from ininteractions among glutenin subunits were also observed. Glu-A1 loci could explain 9.0-13.0% of the variances of peak time, peak value, and peak integral, Glu-B1 loci could explain 9.8-17.1% of the variances of peak time, peak integral, and Glu-D1 loci could explain 8.9-32.6% of the variances of peak time and peak integral at Beijing location; While Glu-A1 loci accounted for 11.4-13.4% of the variances of peak time, peak value, and peak integral; Glu-B1 loci accounted for 5.3-6.7% of the variances of peak time, peak integral; Glu-D1 loci accounted for 33.6% and 29.4% of the variances of peak time and peak integral at Jinan location; whereas Glu-A1 loci could explain 5.4% of the variance of peak integral; Glu-B1 loci could explain 6.3-20.3% of the variance of peak time, peak value and peak integral; Glu-D1 loci could explain 23.1% and 25.7% of the variances of peak integral and peak time at Anyang location. Mixograph peak time and peak integral were mainly influenced by Glu-D1 loci, whereas peak value was mainly influenced by Glu-A1 and Glu-B1 loci.3.Grain hardness, protein content, and major Mixograph parameters including peak time, peak value, and peak integral of totally 106 advanced lines with marker of 5+10 glutenin subunit assisted selection from 5 crosses were analyzed. The result indicated that the frequency of 1Dx5+1Dy10 was higher than the other glutenin subunits from the donor quality parents in four of the five crosses. The lines with 5+10 glutenin subunit at GluD1 locus always had better Mixograph properties and higher quantities of Gluenin, HMW-GS, LMW-GS, Glu-D1 than those with alleles 2+12. Combined with field selection for agronomic characteristics, marker assisted selection could be used efficiently to improve target trait as wheat quality.
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