The Formation Time, Accumulation Of Glutenin Subunits, The Pentosans Contents And Their Relationships With Quality Traits Of Different End Use Wheat Varieties

The contribution of high molecular weight glutenin subunits(HMW-GS) to bread quality has been extensively researched and proved,while the effect of low molecular weight glutenin subunits(LMW-GS) in quality trait of wheat is still inconsistent among findings.In recent years,it's thought that estimation of wheat quality cannot only limit to the research of protein composition,the absolute content and the comparative content of glutenin in wheat are also important to the quality.This may explain why "good" at HMW-GS composition in wheat cannot guarantee good quality.Few reports on the relation of wheat pentosan and quality have been seen in China though a plenty of this research are available abroad.Therefore,it's of importance to carry out this aspect of study among varieties of Chinese wheat.In the past,the studies of wheat quality research were mainly focused on the physics and chemistry characteristic of proteins and starch,with less emphasis on the end product,leading to the disjunction of wheat breeding and its production.The characterization of the composition and content of HMW-GS and LMW-GS as well as their formation and accumulation,the identification of genetic resources with low pentosans contents are very important for the wheat quality improvement.In the present research,seven wheat cultivars of different quality and Triticum compactum were used to study the formation time,accumulation intensity of HMW-GS and LMW-GS and the relationship between the formation or accumulation and grains filling rate.The result showed that1.During the grain filling process,the emergence time and accumulation intensity of HMW-GS were different among these cultivars.After anthesis of 10 days,no subunits can be investigated in cultivars of Ningmai 9 and Yangmai 158;while they formed completely 15 DPA(days post anthesis).And Yangmai 13,PH85-16 and Yannong 15 formed the x-type subunits firstly at 10DPA,and then formed.y-type subunits 15DPA,while Triticum compactum and PH82-2-2 formed all the HMW-GS at 10DPA.The accumulation of HMW-GS reached the maximum at 30DPA or 35DPA.2.In respect to LMW-GS,Ningmai9,Yangmai13,Yangmai158 and PH85-16 had no LMW-GS at 10DPA,while Triticum compactum had formed LMW-GS at B-area with light band and started to form at C-area with few light bands.Also at 10DPA,the formation of LMW-GS in B-area of PH82-2-2,Yannong15 and Annong 92484 started in the way as Triticum compactum did at the C-area.The band number increased with time,and at 15DPA LMW-GS in C-area had already formed in all the varieties.Simultaneously,the already formed bands showed deeper in colour,indicating more proteins were accumulated.The accumulation of LMW-GS achieved a tiptop at 30DPA or 35DPA.25 to 30 days after anthesis,the x/y proportion and the grain filling rate increased suddenly,and the filling rate of the High-gluten wheat was quicker than that of the Low-gluten.3.The pentosans contents were different among these cultivars,with higher pentosans content in High-gluten wheat varieties than that in the Low-gluten wheats.The content of water-soluble pentosan in Low-gluten wheats had an inverse correlation with the ductility and the biscuit diameter.The water-insoluble pentosan and the total pentosans content also showed a remarkable inverse correlation with the biscuit diameter besides a richer relevance with Alveograph parameters and the RVA parameters.These finding provided the basis for the wheat pentosan improvement.This research confirmed Ningmai9 and Yangmai13 were truly the high quality biscuit wheat.And the Triticum compactum's biscuit diameter,thickness,diameter/thickness were close to these two Low-gluten wheats,with exception of a lower pentosan content and higher protein content,charactering the advantages of Low-gluten and the high protein content.Thus,the Triticum compactum could be a new resource for high protein content biscuit making.4.According to quality of biscuit made from these wheats,the Low-gluten wheat displayed a good biscuit quality in this wheat area,in which Yangmai13 was extremely close to the AACC standard,suggesting the Low-gluten wheat had formed a stable quality in Jiangsu's Middle Low-gluten wheat area.This research provided more reliable quality basis for the wheat breeding.After growing in Jiangsu's Middle Low-gluten,the gluten content of High-gluten varieties from Huanghuai Middle High-gluten wheat area almostly did not change,but stability time of them had a big range decent.