Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/6/2000
Publication Date: 10/15/2000
Citation: Hegstad, J.B., Kianian, S.F., Doehlert, D.C., McMullen, M.S., Elias, E.M. 2000. Direct allele selection for development of waxy and partial-waxy durum wheat [abstract.] Agronomy Abstracts. p.106.
Technical Abstract: Waxy genes (Wx) encode a granule-bound starch synthase essential for amylose synthesis. Mutations in these loci can result in significant reductions in amylose levels. The lack of amylose in the caryopsis is commonly referred to as the waxy phenotype. Durum (2n=4x=28; AABB) wheat is the grain of choice for high quality pasta products. Low amylose content has been implicated with desirable noodle making quality in hexaploid wheat (2n=6x=42; AABBDD). Hitherto, no durum wheat cultivar was available exhibiting the complete waxy phenotype. We report the development of waxy durum lines by introgression of wx genes from the partial waxy hexaploid wheat 'Ike' into durum cultivar 'Ben'. Marker-assisted selection facilitated the development of full waxy lines possessing both the wxA and wxB alleles, as well as partial waxy lines possessing either the wxA or wxB alleles, respectively. A clone of the waxy gene from oat was utilized for selection of the respective waxy alleles on durum chromosomes 4A (wxB) and 7A (wxA). Phenotypic screening based on staining with iodine also was utilized for the identification of waxy plants and plants carrying wx alleles. Other molecular markers - including RFLPs, AFLPs, and STSs - are being evaluated for utility of wx allele selection. The relative amounts of remaining donor chromatin and relative agronomic effects also remain to be estimated. Lines are developed to BC5F2; purification trials and generational advancement will follow.