Location: Cereal Crops ResearchTitle: Decades of Breeding Scab Resistant Durum Wheat in North Dakota: Challenges and Successes Author
|Elias, Elias - North Dakota State University|
|Manthey, Frank - North Dakota State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/20/2018
Publication Date: 9/19/2019
Citation: Elias, E.M., Xu, S.S., Manthey, F.A. 2019. Decades of Breeding Scab Resistant Durum Wheat in North Dakota: Challenges and Successes [Abstract]. International Conference From Seed To Pasta III: A Sustainable Durum Wheat Chain for Food Security and Healthy Lives. September 19-21, 2018. Bologna, Italy. https://www.fromseedtopasta.com/wp-content/uploads/2018/09/Elias_Elias.pdf
Interpretive Summary: The major diseases of wheat include stem rust, leaf rust, stripe rust, and powdery mildew. Finding new genes that control these diseases is a major goal of plant breeders. Wild relatives of wheat, including a goatgrass species called Aegilops markgrafii (Ae. markgrafii), are good sources of new genes. A set of six wheat lines, each carrying a single additional chromosome from Ae. markgrafii designated as B thru G, was previously produced. We studied these lines to determine which of the Ae. markgrafii chromosomes carry genes for disease resistance, to determine the relationship of the Ae. markgrafii chromosome to the wheat chromosomes, and to discover molecular markers associated with each Ae. markgrafii chromosome. We found leaf rust resistance was associated with chromosome B, and powdery mildew resistance was associated with chromosomes D, E, F, and G. We found no resistance to stripe rust associated with any Ae. markgrafii chromosome. A prior study had found stem rust resistance associated with chromosomes C and D. Thus, each Ae. markgrafii chromosome conferred resistance to at least one disease. We found 132 molecular markers that were associated with one or more Ae. markgrafii chromosomes. These markers were used to establish the relationship of the Ae. markgrafii chromosomes to the wheat chromosome groups. We determined that chromosomes B, C, D, E, F, and G were related to wheat chromosome groups 2, 5, 6, 7, 3, and 4, respectively. The disease data, molecular markers, and chromosome groupings will allow for transfer of Ae. markgrafii genes to wheat.
Technical Abstract: Durum wheat (Triticum durum Desf.) is one of the major cereal crops in the world and its production in North Dakota accounts for about 60% of the U.S. production. Durum wheat is very susceptible to Fusarium head blight (FHB) caused by the fungus Fusarium graminearum Schwabe (telomorph Gibberella zeae (Schw.) Petch. Breeding for FHB resistance is a major strategy for reducing the impact of FHB on durum wheat. However, the lack of good resistance sources in durum wheat has hindered the development of FHB resistant durum wheat cultivars. The current level of resistance found in North Dakota durum cultivars is much lower than that found in hexaploid wheat germplasm. Attempts to introduce resistance genes from the FHB resistant hexaploid Sumai 3 have been challenging because of genetic linkage drag of undesirable traits and other complex issues. Finding sources of high level FHB resistance in durum wheat germplasm has become a priority. To date, approximately 8,000 durum accessions from worldwide collections and 6,000 accessions from ICARDA have been screened for FHB reactions, but only a small number of accessions were found to be moderately resistant. Unadapted germplasm Tunisian lines, other tetraploid relatives such as T. carthlicum, T. dicoccum, T. dicoccoides (Langdon-T. dicoccoides 3A and 7A substitution lines), and hexaploid line PI 277012 have been used in the breeding program as sources of resistance. Similarly to Sumai 3, their use has been challenging because of genetic linkage drag. The limited amount of native resistance in the adapted germplasm has become important in the breeding program. Using native resistance, the recently released ND Riveland (2017) has lower disease severity and DON levels combined with low cadmium uptake when compared with all other cultivars grown in North Dakota. However, searching for new FHB sources of resistance will remain a priority and a continuous process.