Evaluation of Bread Wheat Varieties to Dominant Races of Stem Rust (Puccinia graminis f. sp. tritici) Pathogen

摘要

Stem rust (Black rust) caused by Puccinia graminis f. sp. tritici is one of the most important air borne diseases of wheat (Triticum aestivum) in the central high lands of Ethiopia, including west and southwest Shewa zones. The pathogen is capable to produce new physiological races that attack resistant varieties and develop epidemic under optimal environmental conditions which results in a serious yield loss. However, information on the reaction of bread wheat varieties to dominant races in west and southwest Shewa zones is lacking. Therefore, the present study was conducted to evaluate the reaction of 12 commonly grown bread wheat varieties by artificial inoculation against the major virulent races at seedling stage in green house (TKTTF and TTKSK) and at adult plant growth stage under field condition (TTKSK). In the green house test, varieties Huluka and Ogena showed resistance to TTKSK and TKTTF races. Likewise, the two varieties showed moderately resistance reaction at adult plant growth stage with terminal severity of below 10%. Whereas, ET-13A2 was susceptible to both races at both plant growth stages. Digalu was susceptible to TKTTF, but resistant to TTKSK at seedling stage, and under field condition it showed severity of 63.3S. The lowest mean AUDPC was recorded on the Ogena, Huluka and Shorima varieties with 37, 52.7 and 103.7 values in the mentioned order. In contrast, the highest mean AUDPC of 1225 on Morocco and 805.8 on Digalu were recorded. Similarly, the maximum mean disease infection rate was also recorded on Morocco and Digalu varieties. Hence, varieties Ogena and Huluka that showed resistance to both virulent races at seedling and adult plant growth stages can be used as sources of resistance in wheat breeding program.