| The study was based on two sets of materials. One set of material was composed of one hundred and fourteen Chinese varieties and advanced lines planted mainly in Huang-huai wheat area and their HMW-GS composition, protein traits, starch traits and hand-made Chinese steamed bread quality traits were measurated, which was used to study the relation between northern style steamed bread quality and wheat quality, and wheat quality traits for making high-quality steamed bread. The other set of material was a population of recombinant inbred lines (RILs) of F8, composed of 131 lines, of which, steamed bread making quality were investigated and the aim was to locat steamed bread quality by QTL mapping. The major results were presented below:(1) Investigation on the quality of wheat varieties and advanced lines planted in Huang-huai wheat area. There were sixteen types of subunit varieties in Glu-1 loci. 1 and null were the main varieties of Glu-A1, 7+8 and 7+9 were the main varieties of Glu-B1, and 2+12 was the main variety of Glu-D1. In addition, the good subunits 14+15 and 5+10 were also found in many wheat varieties and their proportions were respectively 16.9% and 22.9%. There were 26 kinds of subunits combinations, and (1, 7+8, 2+12), (1, 7+9, 2+12), (null, 7+8, 2+12) and (null, 7+9, 2+12) were the main types. Protein traits starch traits and steamed bread quality traits were significantly different among the lines. The variation coefficients of most protein traits were above 40% or 60%. To starch traits, the most were above 10%. Among the quality of steamed bread,there were also significant differences, especially for steamed bread appearance, color, structure, elasticity, stickiness and smell, which variation coefficients were above 20%.(2)Association between wheat quality and steamed bread quality. HMW-GS influenced steamed bread volume, weight, specific volume, structure and stickiness significantly, however, little effect on steamed bread appearance, color, elasticity and smell. We firstly found that steamed bread made by wheat varieties, which had subunit 4+12, had good appearance and structure and steamed bread made by wheat varieties that had subunit 14+15 had good stickiness but bad appearance and structure. We also found that varieties that had the subunit combination (1,17+18,5+10) had good steamed breadvolume and specific volume, varieties that had the subunit combination (N,7+9,2+12)had good steamed bread structure ,varieties that had the subunit combination(1,14+15,2+12)had good steamed bread color and varieties that had the subunit combination (null,14+15,2+12) had good steamed bread stickiness. The results of simple correlation analysis showed that most protein traits were significantly and positively associated with steamed bread volume, weight and specific volume, and significantly and negatively associated with appearance, structure, elasticity and total score; while most of starch traits significantly and positively associated with steamed bread appearance, structure, elasticity and total score. We firstly studied the relation between GMP content, swelling power, peak time and pasting temperature time and steamed bread quality.The results of step multiple regression and path coefficient analysis indicated that steamed bread quality, except for color which was mainly influenced by protein traits, were effected by both protein traits and starch traits and protein traits influenced steamed bread quality mainly by direct effect, while starch traits impacted steamed bread by the co-action of direct effect and indirect effect.(3)According to the standard error and mean of wheat quality traits that had significant differences in the three grades of steamed bread, we put forward the referenced values and ranges of wheat quality traits for making high-quality northern style hand -made steamed bread.(4)Analysis of QTL Mapping for steamed bread quality was studied firstly. Totally 4 QTLS were detected for steamed bread volume, specific volume, appearance and stru... |
