Field Evaluation of Bread Wheat (Triticum aestivum L.) Genotypes for Stripe Rust (Puccinia striiformis W.) Resistance in Arsi Highlands of Oromia Region, South -Eastern-Ethiopia

Abstract

Wheat is one of the world's most important crops whose grain production is increasing year after year. However, the emerged virulent stripe rust races at one point of the world spread to the rest of wheat producing countries by wind as well as human travels and damaged popular resistant wheat cultivars thereby posed food insecurity. This study was carried out with the aim to identify possible sources of stripe rust resistance among Ethiopian bread wheat pipelines for durable resistance breeding. Twenty-eight advanced bread wheat pipelines, local susceptible and resistant check cultivars Kubsa and Wane respectively were field tested in randomized complete block design with three replications across two stripe rust hot-spot locations for their slow rusting characteristics. Slow rusting resistance at the adultplant stage was assessed through the determination of final rust severity (FRS), average coefficient of infection (ACI), and relative area under disease progressive curve (rAUDPC). Among the twenty-eight, 24, 2 and 2 genotypes displayed high, moderate and low level of slow rusting over two locations respectively. The results revealed that wheat lines, ETBW- 8858, ETBW-8870, ETBW-8583, ETBW-8668, ETBW-8595, ETBW-8684, ETBW-9548, ETBW-9549, ETBW-9552, ETBW-9554, ETBW-9558, ETBW-9559, ETBW-9560, ETBW-875, ETBW-8802, ETBW-8862, ETBW- 8804, ETBW-8896, ETBW-9556, ETBW-9557, ETBW-8991,ETBW-9486,ETBW-9556 and ETBW-9561 had low values of FRS, ACI and rAUDPC and were regarded as good slow rusting lines. Strong positive correlations were observed between different parameters of slow rusting. As compared with susceptible, resistant check variety and other test lines, three lines namely. ETBW-8684; ETBW-9558 and ETBW-8751 are high yielders and could be released for production. Twenty-four lines with high and moderate levels of slow rusting and expected to possess both major and minor resistance genes could be used for durable stripe rust resistance breeding in wheat. However, is advised to postulate inherent resistance genes in these lines and their seedling susceptibility for providing fruitful recommendations.