Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2005
Publication Date: 4/25/2006
Citation: Xu, S.S., Cai, X., Wang, T., Harris, M.O., Friesen, T.L. 2006. Registration of two synthetic hexaploid wheat germplasms resistant to hessian fly. Crop Science. 46:1401-1402. Interpretive Summary: Hessian fly is one of the serious pests of wheat around the world and it is found in all major wheat-growing areas in the United States. Outbreaks of Hessian fly can cause serious yield losses in wheat production. Although various approaches can be applied to the control of the pest, the most effective and efficient approach is to deploy wheat cultivars carrying genetic resistance. Thus far, a total of 31 resistance genes to Hessian fly have been identified in wheat and related species and some of them have been used in commercial wheat cultivars. Since the fly could overcome the defenses of resistant varieties by evolving into new strains, there is a need to search for new resistance and to develop adapted germplasms with new resistance. Synthetic wheat, developed by combining genetic factors from tetraploid wheats and a goat-grass species (Aegilops tauschii), have been proved as an excellent source with potential new resistance to Hessian fly. In previous studies, we identified three spring-type synthetic wheat lines (SW8, SW34, and SW39) highly resistant to Hessian fly. Since these synthetic wheat lines have the same genetic constitutions as bread wheat, the resistance genes can be directly transferred into bread wheat using conventional breeding approaches. By registering theses synthetic wheat lines, wheat breeders will be able to use them to develop bread wheat cultivars resistant to Hessian fly.
Technical Abstract: Technical Abstract: Three spring-type synthetic hexaploid wheat (SHW) lines SW8, SW34 and SW39 were released as germplasms with resistance to Hessian fly [Mayetiola destructor (Say)]. In the 1980s, USDA geneticist L.R. Joppa developed a number of SHW lines from partially fertile F1 hybrids between ‘Langdon’ durum wheat (Triticum turgidum L. ssp. durum) and various accessions of Aegilops tauschii Cosson. In previous study, we evaluated 39 of these SHW lines and Langdon for resistance to Hessian fly Great Plains (GP) biotype. The results indicated that SW8 (Langdon/A. tauschii CIae 25), SW34 (Langdon/A. tauschii RL 5544), and SW39 (Langdon/A. tauschii RL 5561) were highly resistant to GP biotype whereas Langdon was susceptible, suggesting that the resistance in the SHW lines was controlled by a gene(s) on the D-genome chromosomes from A. tauschii. Thus far, five (H13, H22, H23, H24, and H26) of 31 Hessian fly resistance genes were identified from A. tauschii. The resistance gene H13 from A. tauschii has been deployed in a soft winter wheat cultivar in the United States. To test if the resistance in SW8, SW34, and SW39 is controlled by H13, we further evaluated the lines for their resistance to a Hessian fly H13-virulent strain, which has the virulence gene vH13 that overcomes the resistance conditioned by H13. The results showed that SW8 was resistant to the H13-virulence strain but SW34 and SW39 were susceptible. Therefore, SW34 and SW39 may carry H13, but the resistance in SW8 is not controlled by H13. Since these SHW lines have the same genomic constitutions as bread wheat, the resistance genes can be directly transferred into bread wheat using conventional breeding approaches. Therefore, the three SHW lines are useful germplasms for wheat breeders to develop bread wheat cultivars resistant to Hessian fly.