Field resistance to wheat stem rust in durum wheat accessions deposited at the USDA National Small Grains Collection

Authors: OLIVERA, PABLO - University Of Minnesota; BULBULA, WORKU - University Of Minnesota; BADEBO, AYELE - International Maize & Wheat Improvement Center (CIMMYT); Bockelman, Harold; EDAE, ERENA - University Of Minnesota; Jin, Yue

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2021
Publication Date: 5/30/2021
Citation: Olivera, P.D., Bulbula, W.D., Badebo, A., Bockelman, H.E., Edae, E.A., Jin, Y. 2021. Field resistance to wheat stem rust in durum wheat accessions deposited at the USDA National Small Grains Collection. Crop Science. 61(4):2565-2578. https://doi.org/10.1002/csc2.20466.
DOI: https://doi.org/10.1002/csc2.20466

Interpretive Summary: Wheat is an important food crop globally. Stem rust is one of the most serious diseases, and successful control of this disease depends on adequate level of resistance in cultivars. Wheat stem rust is a re-emerging disease posing a significant threat to durum wheat production worldwide. The narrow basis of stem rust resistance in modern cultivars underscore the need for identifying and incorporating new effective genes in the durum wheat breeding programs. We evaluated 8,245 spring durum wheat accessions deposited at the USDA National Small Grains Collection (Aberdeen, ID, USA) for resistance in field stem rust nurseries in Debre Zeit, Ethiopia, and St. Paul, MN (USA). Four hundred and ninety-one (6%) accessions exhibited resistant to moderately susceptible responses after three field evaluations at Debre Zeit and two at St. Paul. Among these 491 entries, 53.8% (n=265) were landraces, and 28.4% (n=139) and 11.4% (n=55) were breeding lines and cultivars, respectively. Results from this study indicated the presence of large number of accessions from diverse origin that can be exploited for diversifying and improving stem rust resistance in durum wheat.

Technical Abstract: Wheat stem rust is a re-emerging disease posing a significant threat to durum wheat production worldwide. The narrow basis of stem rust resistance in modern cultivars underscore the need for identifying and incorporating new effective genes in the durum wheat breeding programs. We evaluated 8,245 spring durum wheat accessions deposited at the USDA National Small Grains Collection (Aberdeen, ID, USA) for resistance in field stem rust nurseries in Debre Zeit, Ethiopia, and St. Paul, MN (USA). Four hundred and ninety-one (6%) accessions exhibited resistant to moderately susceptible responses after three field evaluations at Debre Zeit and two at St. Paul. Among these 491 entries, 53.8% (n=265) were landraces, and 28.4% (n=139) and 11.4% (n=55) were breeding lines and cultivars, respectively. Breeding lines and cultivars displayed a higher level of resistance compared to the landraces. Resistant to moderately susceptible entries were identified from 37 countries. Nearly 70% of these entries were originated from Ethiopia (38%), Mexico (12%), Egypt (10%) and USA (9%). Eight additional countries, including Portugal, Turkey, Italy, Canada, Chile, Australia, Syria, and Tunisia contributed to 19% of the resistant to moderately susceptible entries. Results from this study confirm the presence of large number of accessions from diverse origin that can be exploited for diversifying and improving stem rust resistance in durum wheat.