This document summarizes a study identifying new sources of resistance to stripe rust in synthetic hexaploid wheat. Stripe rust is a major wheat disease that causes significant yield losses in Ethiopia. The study evaluated 764 synthetic hexaploid wheat lines for resistance to stripe rust through seedling and field tests in Ethiopia and Syria. 173 lines exhibited resistance or moderate resistance at the adult plant stage across locations. Some resistant lines were also resistant to stem rust. The synthetic hexaploid wheat lines identified in this study provide potential new sources of resistance that can be used in wheat breeding programs to develop cultivars with improved resistance to stripe rust.

1. Sources of Resistance to Stripe Rust in Synthetic Hexaploid Wheat Habte-Mariam Z., A.Badebo and W. Denbel K. Nazari, O.Francis EIAR

5. In 1988, on variety, “Dashen” (VEE’S’)

7. (6E16) Yr 6, 7, 8 (82E0) Yr7, 9, 10, SU (6E6) Yr6,7, 6+,7+ (70E16) Yr6,7, 8, SU (82E16) Yr7, 9,10, SU 8 (86E0) Yr 7, 9,10, SU, 6 (38E16) Yr6, 7, 8, SD (70E150) Yr6,7,6+, 7+, 8, SU, 2+ (70E30) Yr6,7, 8, SU, 3N, 6+, 7+ (38E150) Yr6, 7, 8, SD, 6+,7+, 2+ (78E30) Yr6,7, 8, SU, 3N, 6+, 7+, 3V (198E158) Yr6,7,6+, 7+, 8, SU, 2+,3N, 9+ (166E150) Yr6, 7, 8, SD, 6+, 7+,2+ ,9+ (78E158) Yr6,7, 8, SU, 3N, 6+, 7+ 3V,2+ (166E158) Yr6, 7, 8, SD, 6+, 7+,2 +, 9+ , 3N (206E158) Yr6,7, 8, SU, 3N, 6+, 7+, 3V,2+, 9+ Evolution of YR races in Ethiopia, 1973-2003 (Badebo et al., 2008) (230E158) Yr6, 7, 8, SD, 6+, 7+,2+ ,9+, 3N, SU

8. Stripe rust races.. Dominant races 1998-2003 in Ethiopia All the commercial bread wheat succumbed to the ‘Kubsa’ race (230E158) at seedling tests in 1998 (Badebo et al., 2008)

11. Primitive cultivars - center of diversity

12. Wild or semi-wild materials- Center of origin

14. Materials and Method Planting materials A total of 764. synthetic hexaploid wheat derived from Aegilops tauschii and Triticum durum and developed in CIMMYT, Australia and ICARDA Seedling test Seedling test was carried out in the greenhouse at ICARDA using a local race of P. striiformis virulent on Yr2, Yr6, Yr7, Yr9, YrA, Yr25 and Yr27 genes, 2010

17. Results and Discussion There was high pressure of stripe rust both in Syria and Ethiopia in 2010 In Ethiopia, the disease appeared unusually early in the season in Arsi zone

18. Stripe rust epidemics The epidemics covered almost all wheat growing regions except in Tigray Most of the commercial bread wheat cultivars were susceptible Durum wheat varieties were resistant

21. Mono-cropping/buildup of spore load?

23. Kulumsa Bekoji Monthly Minimum Temperature (oC)

24. Challenges and opportunities? Screening of synthetic hexaploid wheat to stripe rust

25. Field test The highest disease scores were noted at Meraro followed by Tel-Hadya. The reaction of check varieties to stripe rust at Meraro, 2010

26. Kulumsa , N= 764 Tel-Hadya, N=749 Frequency (%) of SHWs under different stripe rust reaction classes at three locations in Ethiopia and Syria, 2010

27. Ethiopia + Syria, N=651 Frequency (%) of SHWs under different resistance groups at adult plant growth stage across locations

28. Seedling test Out of 644 SHWs evaluated, 36.8 % exhibited resistance whereas the rest 63.2% were susceptible at seedling stage

29. Frequency (%) of SHWs under different reaction classes after being tested both at seedling and adult plant growth stage at Tel-Hadya, 2010