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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.

Advanced breeding lines with acceptable resistance and tolerance levels to broomrape is an important way of decreasing yield loss. The objective of this research was to assess the yield stability of faba bean genotypes under diverse broomrape (Orobanche crenata) prone production environments. Six faba bean genotypes were tested across six environments. The AMMI analysis showed significant (P<0.01) genotype, environment and genotype by environment interaction and the environment explained higher sum of square for the response variable grain yield. The AMMI one gives the best model fitness for the grain yield and broomrape number. Using the AMMI 1 biplot, polygon view of the GGE biplot and comparison of genotypes based on ideal genotype, the genotype ILB4358 was higher yielder and stable with lower Orobanche number followed by the genotype Sel.F5/3382/2003-4. Using the AMMI biplot analysis E3 (Adigolo, 2011) and E4 (Adigolo, 2012) were unfavorable environments, while, E1 (Awliegara, 2011), E2 (Awliegara,), E5 (Kolatsihidi, 2011) and E6 (Kolatsihidi, 2012) were favorable testing environments.

Wheat stem rust caused by Puccinia graminis f. sp. tritici is a disease that causes complete annihilation of wheat crops over wide areas during epidemic years. The highland of Ethiopia is considered as a hot spot area for the development of stem rust complex. Hence, this study was carried out to detect the virulence diversity of P. graminis f. sp. tritici in Southern Tigray. The findings of this paper were based on race analysis through inoculation of stem rust populations, isolation and multiplication of single-pustule of the pathogen and race determination by inoculating on stem rust differential hosts. The phenotypic characterization of P. graminis f. sp. tritici resulted in identification of 20 races from 32 isolates, which included the most prevalent races TTSNK, RRJJC and HRJJC with a frequency of 9.4% each and the most virulent races TTKSK and TTSSK each making 85% of Sr genes ineffective. Three important races (TTSSK, TTSNK and RRTTF) are new to the study area and the country (Ethiopia) as a whole putting a significant wheat proportion at risk. Among 20 wheat stem rust differential hosts, four were found effective for 75% and more of the races identified. Differential host carrying Sr24 was effective to all, while gene SrTmp was effective to 90% of the races followed by Sr17 and Sr31 each effective for 75%. In contrast, differential hosts carrying SrMcN, Sr9b, Sr9g and Sr10 were ineffective to 96.9, 93.8, 87.5 and 81.2% of the isolates tested, respectively. Thus, use of effective Sr genes such as Sr24 and SrTmp in single cultivar through gene pyramiding has paramount importance as the additive effects of several genes gives the cultivar a wider base  stem rust resistance along with periodic race survey.

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