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 or the transgenic events studied, Dy10-E and B52a-6, ovenexpress HMW-GS IDY10, while the third event, Dx5 +Dy10-H, overexpresses HMW-GS IDx5 and to a much lesser extent. IDY10. 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 bread-making quality by optimizing the level of over-expression or by development and characterization of additional events
