Distribution and Physiologic Races of Wheat Stem Rust in Tigray, Ethiopia

Abstract

Wheat stem rust caused by Puccinia graminis f. sp. tritici is amongst the biotic catastrophic diseases because of its ability to cause complete annihilation of wheat crops during epidemic years. The highland of Ethiopia is considered as a hot spot for the development of stem rust complex. Hence, this study was conducted to investigate the distribution and intensity; to detect the virulence diversity of the pathogen in South Tigray. The findings of this paper were based on stem rust surveys to compute the intensity; race analysis by inoculating isolates on to the 20 differential hosts. During the survey, 66 wheat fields were examined in 2010, of which 33.3% were affected. The overall mean incidence and severity of the disease were 15.6 and 8.5%, respectively. A total of 20 races were identified from 32 isolates, which included the most prevalent races TTSNK, RRJJC and HRJJC. Most of the the genes possessed by the differentials were ineffective against one or more of the tested isolates except Sr24. Sr genes 24 and Tmp were effective in 100 and 90% of the races, respectively. In contrast, SrMcN and Sr9b were ineffective to 96.9 and 93.8% of the isolates tested, respectively. Thus, use of effective Sr genes singly or incombination with other genes through gene pyramiding has paramount importance as the additive effects of several genes offer the cultivar a wider base stem rust resistance along with periodic race survey to track further virulence evolution.

Race and virulence characterization of Puccinia graminis f. sp. tritici in China

“…Maintaining dynamic information on pathogens is the basis for breeding disease resistance. Although wheat stem rust has not been common in recent years, understanding the population structure, virulence diversity, and distribution of Pgt at various times and in different locations is essential for selecting effective resistance genes to control this disease [ 6 ]. Furthermore, work on detecting and identifying races of Pgt has not stopped.…”

Development of wheat germplasm for stem rust resistance in eastern Africa

“…The least ACI value was recorded for elite line ETBW6655 (ACI=0.75). Hawi is postulated to have seedling stem rust resistance gene(s), Sr30+/ Sr31 (Naod et al, 2005), both of which are not effective to the prevalent stem rust races in the major wheat growing regions of Ethiopia (Admassu and Fekadu, 2005;Admassu et al, 2009;Abebe et al, 2012). Bread wheat cultivar ET13A2, was resistant to moderately resistant to the prevalent pathotypes of stem rust in Kenya and Ethiopia.…”

Detection of Ug99 (TTKSK) of wheat stem rust fungus and new virulence races of Puccinia graminis f.sp. tritici in Egypt

“…Wheat national production-consumption gap is a major economy dilemma in Egypt, where 49 % of wheat national consumption was imported in 2013 and it will reach 63 % under climate change in 2030 (Ouda and Zohry, 2017). The major biotic factors that limit wheat production in the country include diseases, insect pests and weeds (Abebe et al, 2012). Stem rust (Pgt), leaf rust (P. triticina) and stripe rust (P. striiformis f. sp.…”