| Wheat is the second most important crop in China after rice. Since mostly medium gluten varieties are used, there is a lack of high gluten and low gluten wheat. The domestic breeders have been breeding high quality wheat varieties with high gluten varieties in recent years to deal with this situation. The protein and starch are the most important substances in wheat kernels, and they are essential for flour properties and bread-baking quality. Some aspects on important protein components and starch properties of wheat were studied in this paper in order to provide basis for genetic improvement of wheat quality.1 The relationships between protein compositions and rheological properties were analyzed by domestic and foreign wheat germplasms. The results showed that the associations between albumin content, globulin content, gliadin content and rheological properties were not obvious. Glutenin content, insoluble protein content were positive correlated closely to dough rheological properties. Direct effects and indirect effects of protein compositions to rheological properties were studied by path analysis, and the line regression equations of protein compositions to main bread-baking quality characters were established. Cross breeding should be used for raising glutenin content and insoluble protein content.2 HMW-GS compositions and protein content, Zeleny sedimentation value, GMP content, amylose content, swelling power of 270 wheat varieties were determined. The results indicated that subunit 1,2, 7, 7+8 and 5+10 associated to high bread quality characters. Combination effects of subunits on bread-baking quality were studied in 3 wheat crosses (different allelic subunits in IB and ID loci of male parent and female parent in every cross). The results demonstrated that the quality scores of subunit combinations were in accordance with rheological properties. There were obvious differences among quality characters of subunit combinations. Bread quality of varieties can be improved by recombination of high quality subunits, and high quality lines have been bred successfully.3 GMP content, main bread quality characters and agronomic characters of 260 wheat germplasms were determined. The results showed that GMP content was positive correlated closely to main bread quality characters. The associations between GMP content and agronomic characters were not obvious. The inheritance of GMP content was fitted to additive-dominant model, and was mainly controlled by additive genes. GMP content is an excellent index to show the bread quality. Because it has high broad heritability, high narrow heritability and less sample determined, it can be used to select bread quality in early hybrid generations of breeding. It is practicable for combining yield and quality in wheat breeding using GMP content as bread quality selecting index.4 Amylose content, swelling power, bread quality characters of 260 wheat germplasms and amylopectin content, starch content were determined. The results showed that extreme negative correlations between amylose content and bread quality characters, and extreme positive correlations between amylopectin content, swelling power and bread quality characters were found. The size anshapes of starch granules of 10 wheat lines were observed by scanning electron microscope. The bread quality characters of lines with large A-type starch granules were better than that with small A-type starch granules. The round or elliptic starch granules were larger than long-round starch granules generally. The analysis results of diallel crosses that the inheritance of amylose content was fitted to additive-dominant model, and the additive effect was slight larger than non- additive effect. The inheritance of swelling power was fitted to additive-dominant model, and the non- additive effect was slight larger than additive effect. There were obvious differences in amylose content and swelling power of varieties grown in different sites. The variation of amylose content and swelling power of varieties wi... |
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