CYTOGENETIC MANIPULATION OF DURUM WHEAT BY CLASSICAL AND MOLECULAR TECHNIQUES
Location: Cereal Crops Research
Title: Registration of a genetic stock DGE-3, a Durum Wheat disomic substitution line involving a wheatgrass chromosome
Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 28, 2012
Publication Date: N/A
Interpretive Summary: Durum wheat or pasta wheat is an important cereal crop. It is an allotetraploid, i.e., has two diverse genomes each in a double dose, derived from its wild progenitors. It has 28 chromosomes, 14 from each of the progenitors. It can tolerate some chromosome imbalance, making chromosome manipulation possible. In our Durum Germplasm Enhancement (DGE) project, we produced an alien disomic substitution 1E(1B) line (in which chromosome 1B was replaced by chromosome 1E) and we named it DGE-3. It has 28 chromosomes (rod-like structure’s in its cells), 26 of which are durum chromosomes and a pair of chromosomes, 1E, derived from a wild relative, diploid wheatgrass. DGE-3 was derived from the addition line DGE-1 that we produced and released in 2008. DGE-3 shows regular meiosis (cell division in its anthers) with 14 pairs of chromosomes, and is fertile. It is similar to its parental durum cultivar Langdon. We verified its chromosomal make-up by sophisticated cytological techniques and by chromosome-specific molecular markers. DGE-3 (PI 663216) has been released as a new genetic stock. Its seed has been deposited in the National Plant Germplasm System, Fort Collins, Colorado.
Durum wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) alien disomic substitution 1E(1B) line DGE-3 (PI 665473) was developed by the U.S. Department of Agriculture – Agricultural Research Service, Northern Crop Science Lab, Cereal Crops Research Unit, Fargo, ND and released in 2012. It was derived from the durum alien disomic addition line DGE-1 (2n = 28 + 2) having 28 durum chromosomes and the chromosome pair 1E of diploid wheatgrass. The pedigree of DGE-3 is PI 645483/Langdon 1D(1B)*5. By crossing the DGE-1 (PI 645483) with durum disomic substitution line 1D(1B), we produced hybrid derivatives with univalents of chromosomes 1A, 1B, 1D, and 1E. We selfed the hybrid derivatives five times and screened each generation for durum homoeologues 1A and 1B. We tested these hybrid derivatives for the presence of the alien chromosome 1E and for the absence of 1D. Using the chromosome-specific molecular marker Xwmc333 for identifying chromosome 1A, Xwgm18 for 1B, Xwmc147 for 1D, and Xedm17 for 1E, we isolated a durum disomic alien substitution line 1E(1B), which is fertile and stable, and has been released as a new genetic stock, DGE-3. This substitution line has 2n = 28 chromosomes that consist of 26 durum chromosomes plus the wheatgrass chromosome pair, 1E, which compensates for the missing 1B pair of the durum cultivar Langdon. The disomic substitution forms 14 bivalents and is meiotically regular and fertile.