Cytological and Molecular Characterization of Homoeologous Group-1 Chromosomes in Hybrid Derivatives of a Durum Disomic Alien Addition Line

Abstract

Earlier, we produced a stable Fusarium head blight (FHB)-tolerant durum wheat (Triticum turgidum L.) alien disomic addition line, DGE-1 (released in 2008), incorporating chromosome 1E of diploid wheatgrass [Lophopyrum elongatum (Host) Á. Löve; 2n=2x=14; EE]. For stable FHB resistance, the ultimate goal would be to transfer resistance from 1E into the durum chromosome 1A or 1B. Such transfer is more likely to occur when these target chromosomes are in a single dose. Therefore, we crossed DGE-1 with 'Langdon' substitution lines 1D(1A) and 1D(1B) and produced hybrid derivatives with chromosomes 1A, 1B, 1D, and 1E in a single dose. As an important first step, we standardized a method to readily identify these group-1 chromosomes. Multicolor fluorescent genomic in situ hybridization that we standardized earlier is useful for such identification but is tedious and expensive. To identify these chromosomes more expeditiously and economically in a large plant population, we also used chromosome-specific molecular markers and identified each of the group-1 chromosomes. We used marker Xwmc333 to identify chromosome 1A, Xwgm18 for 1B, Xwmc147 for 1D, and Xedm17 for 1E. Xedm17, which profiles chromosome 1E, also generated two characteristic bands for chromosome 1D and may therefore be useful in identifying both chromosomes simultaneously.