Wheat is one of the most important cereal crops of Ethiopia. Stem rust caused by Puccinia graminis f. sp. tritici is amongst the biotic factors which can cause up to 100% yield loss if susceptible cultivar grown and epidemic occurs. The highland of Ethiopia is considered as a hot spot for the development of stem rust diversity. This study was carried out to determine virulence diversity and race distribution of P. graminis f. sp. tritici in Ethiopia. Eighty (80) wheat stem rust samples were collected in 2013 cropping season from Oromia, Amhara and Tigray region. Of the samples collected, 66 were analyzed on to the 20 stem rust differential lines. A total of 9 races were identified, which includes TTKSK, TTKTF, TTKTK, JRCQC, TKTTF, TTKSC, TRTTF, SRKSC and RRKSF. Race TTKSK was dominant and widely distributed in the Oromia and Amhara regions with 52% frequency; it was not isolated in Tigray region. The most virulent and new race, TKTTF which causes localized stem rust epidemic in Bale and Arsi was predominantly distributed in Oromia region with 36.4% frequency value. Most of the genes possessed by the differentials were ineffective against one or more of the tested isolates. Only stem rust resistance gene 24 was found to confer resistance to all of the races isolated in this study. This gene could be used in combination with other genes through gene pyramiding in breeding for resistance to stem rust in Ethiopia.

Four improved bread wheat varieties; Mandoyu (WORRAKATTA/PASTOR), Sanate (14F/HAR1685), Obora (UTIQUE96/FLAG-1) and Dambel (AGUILAL/3/PYN/BAU//MILAN) are developed from ICARDA materials and released in 2014 and 2015, respectively for highland and mid altitude areas of Bale and similar agro-ecologies. The new varieties were tested along with three standard checks (Madawalabu, Sofumer and Tusie) and one local check (Hollandi) at three environments in 2011 to 2012 and 2012 to 2013, respectively during main cropping seasons. The two years data of regional variety trial combined over locations and years provide the newly released varieties showed that superior in grain yield performance, stability, and wide adaptation. The four newly released varieties have good protein content, good physical grain quality, resistant to stem rust, moderately susceptible to yellow rust, moderately resistant to septoria leaf blotch and comparable for leaf rust disease with the checks. The variety Mandoyu, Sanate, Obora and Dambal have been demonstrated and are being cultivated by farmers for production purpose. Hence, the cultivation of these newly released improved bread wheat varieties in the highland and mid altitude areas of major wheat growing environments of the country is highly recommended. This new variety given local name Mandoyu, Sanate, Obora and Dambel, respectively.

Bread Wheat is one of Ethiopia's most important cereal crops in terms of area allocated, volume produced and the number of farmers engaged in its production. However, its production and productivity is curtailed by biotic and abiotic factors. Among biotic factors, wheat yellow rust caused by Puccinia striiformis f.sp.tritici is the most important disease. Field experiment was conducted to assess the effect of environment on wheat varieties' yellow rust resistance and yield performance at three locations, Sinana, Agarfa and Ginir in Bale in 2012 main cropping season. Six bread wheat varieties having different level of resistance to yellow rust were used in the experiment. Plots were arranged in randomized complete block design in three replication. Environment had a significant effect on epidemic development of yellow rust through its effect on growth and progress rate of the pathogen. The test locations were different in their weather variables and created significant difference (p≤ 0.05) in yellow rust severity among the varieties. Due to weather variables across locations, the same variety responded differently to yellow rust severities at different locations. Environment had varying effect on yield and yield related traits. The tested bread wheat varieties had significant difference (p ≤ 0.05) for all yield-related traits at all locations. There was inconsistent behavior of the varieties across locations for yield and yield components. Variation in the environmental factors affected wheat varieties' yellow rust resistance and yield performance. The varieties responded differently in their resistance to yellow rust and yield performance when exposed to different environments varying in minimum and maximum temperature regimes and rainfall status.

No abstract