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Association Between % SDS-Unextractable Polymeric Protein (%UPP) and End-Use Quality in Chinese Bread Wheat Cultivars

¹Institute of Crop Science, National Wheat Improvement Centre/The National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, 12 Zhongguancun South Street, Beijing 100081, China. ²Institute of Agricultural Biology and Technology, Jiangsu Academy of Agricultural Sciences, 50 Zhonglin Street, Nanjing 210014, Jiangsu, China. ³CIMMYT China Beijing Office, C/O CAAS, Beijing 100081, China. ⁴Corresponding author. Phone: +86-10-62170333. Fax: +86-10-82108547. E-mail: zhhe@public3.bta.net.cn ⁵Crop Research Institute, Ningxia Academy of Agricultural and Forestry Sciences, Yongning 750105, Ningxia Autonomous Region, China.

Trial I, with 33 spring cultivars, and trial II, with 21 winter cultivars, sown in four environments in the northwestern China spring wheat region and northern winter wheat region, respectively, were used to study the effect of genotype and environment on the size distribution of polymeric proteins. Association between quantity and size distribution of polymeric protein and dough properties (both trials) and northern-style Chinese steamed-bread (CSB) (trial I) and pan bread (trial II) qualities were also investigated. In trial I, all protein attributes, such as flour protein content, SDS-extractable polymeric protein in the flour (EPP), SDS-unextractable polymeric protein in the flour (UPP), and percent UPP in total polymeric protein (%UPP), were largely determined by environment, whereas variation in dough strength resulted from variation in UPP and %UPP across environments. In trial II, EPP was largely determined by environment, and UPP and %UPP were largely determined by genotype. These differences might result from different levels of protein content and dough strength in the two trials. The EPP was positively correlated with dough extensibility and was generally negatively correlated with dough stability and maximum resistance in both trials. However, %UPP was significantly positively correlated with dough stability and maximum resistance and end-use quality in both trials. In trial I, correlation coefficients between %UPP and maximum resistance and CSB score were r = 0.90 and 0.71, respectively, whereas in trial II, the correlation coefficients between %UPP and maximum resistance and pan bread score were 0.96 and 0.87, respectively. Therefore, selection for high %UPP together with high-quality glutenin subunits should lead to improved dough strength and end-use quality in Chinese wheats.