Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/1997
Publication Date: N/A
Interpretive Summary: The amount of protein present in the grain of durum wheat has a marked effect on the quality of the spaghetti and other pasta products produced. In general, an increase in the amount of protein in the semolina or flour improves the quality of the product. A gene that increases protein in the seeds was transferred to durum wheat from a wild emmer wheat native to Israel. This gene previously was shown to be present on chromosome 6B. A new method for determining the chromosomal location of the gene was developed. The gene was located close to the centromere. It is difficult to breed for increased protein, because protein varies depending on growing conditions. But, certain other genes close to the gene for high grain protein content can be easily identified using molecular genetic methods. These genes close to the gene for high grain protein can be used to identify those plants that carry the high protein gene. These methods will allow the plant breeder to rapidly incorporate the gene for high grain protein content into new cultivars, and thus improve the quality of durum products.
Technical Abstract: A 'Langdon' durum wheat line with a pair of 6B chromosomes from an accession of Triticum turgidum L. var. dicoccoides previously was shown to have a gene(s) for high grain protein content (GPC). The objectives of this study were to develop a mapping population segregating only for genes on chromosome 6B, map the gene(s) for high GPC, and identify closely linked markers for use in marker-assisted breeding for this trait. The 6B mapping population was grown in replicated field trials and evaluated for GPC. A RFLP map of this population was available. MAPMAKER/QTL provided strong evidence that a gene(s) for high GPC is located near the centromere of 6B. The most likely location for the gene(s) is in the short arm between Xabg387-6B and Xmwg79-6B. The LOD score for this interval is 18.9. Segregation in this segment accounted for 66% of the variation in GPC. Eleven additional markers have been mapped within seven cM of the midpoint of Xabg387-6B and Xmwg79-6B. One or more of these markers should be useful in marker-assisted breeding for high GPC in durum wheat. One reason for the success of this mapping effort may be that segregation in the mapping population is largely confined to chromosome 6B. Similar mapping populations for the other durum chromosomes also may be useful in identifying map locations for QTLs such as those for yield and disease resistance.