CYTOGENETIC MANIPULATION OF DURUM WHEAT BY CLASSICAL AND MOLECULAR TECHNIQUES
Location: Cereal Crops Research
Title: Registration of DGE-2, a durum wheat disomic alien substitution line 1E(1A) involving a diploid wheatgrass chromosome
Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 7, 2012
Publication Date: May 1, 2012
Citation: Jauhar, P.P., Peterson, T.S. 2012. Registration of DGE-2, a durum wheat disomic alien substitution line 1E(1A) involving a diploid wheatgrass chromosome. Journal of Plant Registrations. 6:221-223.
Interpretive Summary: Durum wheat or pasta wheat is an important cereal crop. It is an allotetraploid i.e., has two diverse genomes in a double dose, derived from its progenitors. It has 28 chromosomes, 14 from each of the parents. It can tolerate some chromosome imbalance, making chromosome manipulation possible. We produced an alien disomic substitution 1E(1A) line and called it DGE-2 (Durum Germplasm Enhancement-2). It has 28 chromosomes, 26 of which are durum chromosomes and a pair of chromosomes, 1E, derived from a wild relative, diploid wheatgrass. The chromosome 1E pair replaces the 1A pair of durum. DGE-2 was derived from the addition line DGE-1 that we produced and released in 2008. The disomic substitution shows regular meiosis with 14 pairs of chromosomes, and is fertile. We verified its chromosomal make-up by sophisticated cytological techniques and by using chromosome-specific molecular markers. The DGE-2 substitution line has been released as a new genetic stock. Its seed has been deposited in the National Plant Germplasm System, Fort Collins, Colorado.
The durum wheat (Triticum turgidum L., 2n = 2x = 28; AABB genomes) alien disomic substitution 1E(1A) line DGE-2 (PI 663216) was developed by the USDA–ARS, Cereal Crops Research Unit, Northern Crop Science Laboratory, Fargo, North Dakota and released in 2011. DGE-2 has 2n = 28 chromosomes, which are comprised of 26 durum chromosomes and a pair of chromosomes, 1E, from a wild relative, diploid wheatgrass (Lophopyrum elongatum (Host) Á. Löve, 2n = 2x = 14; EE genome). The chromosome 1E pair replaces the 1A pair of the durum cultivar ‘Langdon.’ The disomic substitution is meiotically regular forming 14 bivalents, and is fertile. The pedigree of DGE-2 is [DGE-1 (2n = 28 + 2)] PI 645483/Langdon 1D(1A)*5. We crossed our alien addition line DGE-1 with Langdon disomic substitution line 1D(1A) and produced F1 hybrid derivatives with chromosomes 1A, 1D, and 1E in a single dose. We selfed these hybrid derivatives five times, and screened each generation for homoeologous group-1 chromosomes 1A and 1B. At the same time these hybrid derivatives were tested for the presence of 1E and absence of 1D. Using chromosome-specific molecular markers Xwmc333 for identifying chromosome 1A, Xwgm18 for 1B, Xwmc147 for 1D, and Xedm17 for 1E, we identified and isolated a disomic alien substitution line 1E(1A) that was stable and is released as a new genetic stock.