Functional Properties and Agronomic Performance of Transgenic Tritordeum Expressing High Molecular Weight Glutenin Subunit Genes 1Ax1 and 1Dx5

Abstract

Two transgenic lines of tritordeum line HT28 have been evaluated under field conditions for agronomic performance and processing quality. One line (line 3) contained the gene encoding for the high molecular weight (HMW) glutenin subunit 1Dx5 and the second (line 8) two genes for HMW subunits 1Ax1 and 1Dx5. The two transgenic lines showed similar agronomic performance which was inferior to the untransformed control line. Phenotypic differences between the transgenic and the control lines were observed for heading date, yield, harvest index, 1000-seed weight, test weight, and grain protein content. Alveograph studies showed that the addition of subunit 1Dx5 (line 3), which accounted for 27% of the total HMW glutenin subunits (HMW-GS), clearly improved the dough quality of tritordeum, increasing the tenacity and the deformation energy. This line showed dough properties as good as those of a good breadmaking wheat variety. In contrast, the addition of HMW-GS 1Ax1 and 1Dx5 together had little effect on the tenacity, extensibility or deformation energy when compared with the control HT28 line, even though they represented 25% and 37% of the total HMW subunit protein respectively.