Quality of synthetic hexaploid wheat containing null alleles at Glu-A1 and Glu-B1 loci.

Triticum turgidum ssp. dicoccon PI94668 and PI349045 were identified as containing null alleles at Glu-A1 and Glu-B1 loci in previous investigation. Sequencing of the respective HMW-GS genes Ax, Bx, Ay and By in both accessions indicated equal DNA lengths with gene silencing caused by 1 to 4 in-frame stop codon(s) in the open reading frames. Six synthetic hexaploid wheat lines were produced by crossing PI94668 or PI349045 with six Aegilops tauschii by spontaneous chromosome doubling of unreduced gametes. As expected, these amphiploids had three different HMW-GS: Dx 3.1(t) + Dy11(*t), Dx2.1(t) +10(t) and Dx2(t) +Dy12(t) in Glu-D1 but double nulls in Glu-A1 and Glu-B1. Quality tests showed that most quality parameters in two T. turgidum ssp. dicoccon parents were very low due to the lack of HMW-GSs. However, incorporation of HMW-GS from Ae. tauschii in six synthetic hexaploid wheat lines significantly increased most quality related parameters. The potential values of these wheat lines in improving the quality of wheat are discussed.