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Quality and Agronomic Effects of Three High-Molecular-Weight Glutenin Subunit Transgenic Events in Winter Wheat¹

¹Joint contribution of the United States Department of Agriculture, Agricultural Research Service and the Department of Agronomy and Horticulture, University of Nebraska-Lincoln. Mention of firm names or trade products does not imply that they are endorsed or recommended by the USDA or the University of Nebraska over other firms or products not mentioned. ²USDA-ARS, 137 Keim Hall, East Campus, University of Nebraska, Lincoln, NE. ³Corresponding author. Email: bob.graybosch@ars.usda.gov ⁴USDA-ARS, Hard Winter Wheat Quality Laboratory, Manhattan, KS. ⁵USDA-ARS, Western Regional Research Center, Albany, CA.

Quality and agronomic effects of three transgenic high molecular weight glutenin subunit (HMW-GS) events were characterized in advanced-generation breeding lines of hard winter wheat (Triticum aestivum L.) in three Nebraska crop years. Two of the transgenic events studied, Dy10-E and B52a-6, overexpress HMW-GS 1Dy10, while the third event, Dx5 +Dy10-H, overexpresses HMW-GS 1Dx5 and, to a much lesser extent, 1Dy10. In addition, novel proteins possessing solubility characteristics defined as HMW-GS were present in Dx5+Dy10-H and B52a-6. Average grain yield of lines derived from the three transgenic events was statistically lower than that of a group of control cultivars and advanced breeding lines, but not lower than the mean values of respective nontransgenic siblings. Grain hardness was influenced by one of the events. Dx5+Dy10-H produced harder kernels than controls, its nontransgenic siblings, and the two additional transgenic events. All three events produced doughs with unusual mixing properties, although not likely to be directly useful in commercial applications. As a consequence, loaf volumes were depressed to variable degrees by the three events. The results indicated that over-expression of HMW-GS could eventually lead to improved breadmaking quality by optimizing the level of overexpression or by development and characterization of additional events.