தாவர நோயியல் & நுண்ணுயிரியல் இதழ்

சுருக்கம்

Reaction of Bread Wheat Cultivars to Recently Emerging, Virulent and Dominant Races of Stem Rust (Puccinia graminis f.sp.tritici) in Ethiopiam

Mosisa Tolossa

Wheat is a top ranked stable food crops among many cereals in Ethiopia. Being important crop in the country, it is constrained by abiotic and biotic factors across many of production areas. Among biotic factor, stem rust is a major disease of wheat crops. Hence, periodic outbreak of new races and loss of resistance deployed in cultivars of the country is a bottle neck for wheat producer. This study was conducted to evaluate 22 bread wheat cultivars against dominant races for examination of major gene contained in the materials. Evaluation of cultivars was done by artificial inoculation at seedling stage against dominant stem rust races in the greenhouse. Twenty two cultivars were evaluated for stem rust seedling resistance gene against 6 races. The virulent and being dominant races assessed from western and south-western Ethiopia, TTKTT, TTKTF, TKTTF, TTRTF, TKKTF and TTKSK race were used for evaluation of cultivars. The Hierarchical cluster Analysis was done to classify cultivar based on infection types using SAS 9.3 version. Frequency and percentage of cultivar resistance to each 6 races was done by IBM SPSS statistics 20. There was no complete resistance observed among the bread wheat Cultivars evaluated at seedling stage as all cultivars allowed lesion formation by the pathogen. Infection type ranged from fleck 1 to 3+ were observed revealing that different genes in both the pathogens and hosts. The percentage and frequency result indicates, >60% of cultivars were showed resistant reaction to TKKTF race than other races. The most virulent and frequently infecting cultivar in current study to 50% of evaluated cultivars was TTKTF race than rest of strains. Moreover, Cluster analysis result indicates, cultivar Huluka, Lemu, Shorima, Hogana, Wane, Millennium, Honqolo and Biqa was classified to moderately resistant to resistance class. Among which cultivars Shorima, Huluka, Millennium and Wane showed stem rust seedling resistance reactions to all races. These bread wheat cultivars tested showed resistance reaction implying the presence of seedling resistance gene and can be used as the potential sources of resistance in the wheat breeding program. Further research should be conducted with the same cultivars against those emerging and remerging races for their polygenic resistance, which is additional indicator of crops reaction at a field.