Molecular cytogenetic characterization and seed storage protein analysis of 1A/1D translocation lines of durum wheat

Two durum wheat [Triticum turgidum L. ssp. durum (Desf.) Husn.] lines carrying the high-molecular-weight (HMW) glutenin subunits (GS) 1 D x 5 + 1Dy10 encoded by Glu-D1d, L252 and S99B34, were characterized using fluorescent genomic in-situ hybridization (FGISH) and microsatellite markers. These two durum lines were derived from the crosses in which the common wheat (T. aestivum L.) 'Len' and durum wheat 'Langdon' (LDN) and 'Renville' were involved. FGISH patterns of the mitotic chromosomes indicated that these two durum lines have one pair of 1AS.1AL-1DL translocated chromosomes in which the terminal region of 1AL was replaced by a homoeologous segment of 1DL. The 1DL segment spans approximately 31% of the long arm of the translocated chromosome. Microsatellite marker analysis confirmed the 1AS.1AL-1DL translocation and determined the translocation breakpoint to be distal to Xgwm357 on 1AL. Seed storage proteins (GS and gliadins) were analysed in these two 1AS.1AL-1DL translocation lines and three sib lines (L092, S99B19 and S99B33) using SDS-PAGE and A-PAGE. The SDS-PAGE and A-PAGE profiles demonstrated that the two low yielding lines (L252 and S99B19) had the low-molecular-weight (LMW) -1 GS encoded by Glu-A3k and Glu-B3s and 1B-encoded gliadins from LDN, and the other three lines (L092, S99B33 and S99B34) with higher yield had LMW-2 GS and 1B-encoded gliadins from Renville, suggesting that undesirable genetic components from LDN might limit substantial improvement of yield. Thus, the translocation lines with 1 D x 5 + 1Dy10 and LMW-2, which are associated with good bread-making and pasta qualities, respectively, in a good genetic background will be useful for developing durum cultivars with dual-purpose end-use. Results from this study demonstrate that the D-genome could play an important role in the genetic improvement of durum wheat and evolution of the A- and B-genomes in tetraploid wheat.