ARS | Publication request: DEVELOPMENT OF WAXY (LOW AMYLOSE) DURUM CULTIVARS.

Submitted to: Wheat Genetics International Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 5, 1998
Publication Date: N/A

Interpretive Summary: Summary: A new type of durum wheat containing the waxy, or low amylose characteristic has been developed. Starch is composed a mixture of a branched carbohydrate polymer called amylopectin, and a straight chain polymer called amylose. Normal durum wheat starch contains about 23% amylose and 78% amylopectin. Waxy starch contains almost no amylose. Durum wheat is used to make pasta. Because amylose leaching from pasta causes loss in pasta firmness, cooking loss, and increased stickiness, we predict that low amylose pasta ought to have improved cooking characteristics. However, at this time we have not generated samples of waxy durum in sufficient quantity to test cooking characteristics.

Technical Abstract: Durum (2n=4x=28; AABB) wheat (Triticum turgidum ssp. durum Desf.) is the grain of choice for the production of high quality pasta products. Investigators have implicated low amylose content conferred by wx (waxy) genes with high noodle making quality in hexaploid wheat. No complete sets of wx genes are present in durum wheat. We report the development of waxy durum lines by introgression of wx genes from a partial waxy hexaploid wheat into durum cultivars. Crosses between adapted durum cultivars and a wx gene donor have been made, and waxy durum F2 lines have been recovered. Lines are being backcrossed to durum cultivars to reconstitute the recurrent parent genotypes. Phenotypic selection based on pollen and half seed staining has been used for the identification of waxy lines and lines carrying wx alleles. Molecular markers - including RFLPs and STS markers - are being evaluated for utility of wx allele selection. Waxy durum lines will be evaluated for starch quality characteristics and processing characteristics.