Oat stem rust, caused by Puccinia graminis f. sp. avenae, is a devastating fungal disease that poses a serious threat to global oat production. In recent years, with the expansion of oat cultivation area and the shortage of resistant cultivars in China, the prevalence of this disease has shown an increasing trend. There is an urgent need to clarify the population structure and virulence characteristics of P. graminis f. sp. avenae for effective disease management and resistance breeding. From 2023 to 2024, this study collected a total of 186 oat stem rust samples from Hebei Province, China. Single isolates were obtained through single-uredinium, and physiological race identification and virulence frequency analysis were conducted using 12 single-gene differential lines. Additionally, two predominant P. graminis f. sp. avenae races were selected to evaluate the seedling and adult-stage resistance of 59 oat cultivars (lines). The results showed that 188 single-uredium isolates were obtained from 158 viable samples (with a survival rate of 85.0%), and seven physiological races were identified: TJD, TJN, TKN, TJB, TBD, TGD, and TJL. Among them, TJD was the predominant race (occurrence frequency 37.7% in 2023 and 38.8% in 2024), TJN was the subpredominant race (28.2% in 2023 and 31.3% in 2024), and the frequencies of the remaining five races were all below 17.6%. This indicates that the P. graminis f. sp. avenae population structure in China is relatively stable with low virulence diversity. All isolates were virulent to Pg1, Pg2, Pg3, and Pg4, while avirulent to Pg6, Pg13, and Pg16. The virulence frequency to Pg10 ranged from 3.1% to 20.8%. In total, 31 (52.6%) oat cultivars were resistant to all tested races of P. graminis f. sp. avenae in the field test in 2023 to 2024. This study supplements global P. graminis f. sp. avenae surveillance data, clarifies the race composition and virulence dynamics of P. graminis f. sp. avenae in northern China, and provides a scientific basis for the integrated management of oat stem rust and the breeding of resistant cultivars.

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is a devastating disease occurring in most wheat growing countries and regions, posing a severe threat to global wheat production and food security. The deployment of resistant wheat cultivars is widely recognized as the most economical, effective, and environmentally sustainable approach for controlling this disease. To identify novel and effective resistance resources, 105 wheat accessions introduced from the United States were evaluated for adult plant resistance against two predominant Chinese P. graminis f. sp. tritici races (21C3CTHQM and 34MKGQM) in field trials conducted during 2023 and 2024. Molecular marker detection was further performed to assess the presence of five known stem rust resistance genes (Sr24, Sr31, Sr25, Sr26, Sr38). Field results across two consecutive years demonstrated that more than 70% of the tested accessions exhibited high levels of resistance to the two P. graminis f. sp. tritici races. Molecular genotyping indicated that 13 accessions (12.4%) carried only the Sr24 resistance gene, two accessions (1.9%) carried only Sr31, and two accessions (1.9%) carried both Sr24 and Sr31. None of the tested resistance genes (Sr24, Sr31, Sr25, Sr26, Sr38) were detected in the remaining 89 accessions. Notably, although over 70% of the wheat accessions displayed stable and high resistance, only 16.2% carried the known resistance genes Sr24 or Sr31. The remaining resistant accessions (84.8%) likely harbor uncharacterized resistance genes, which can serve as valuable and novel genetic resources for wheat stem rust resistance breeding.

Transcription factors are pivotal molecules involved in transcriptional and post-transcriptional regulation in plants, playing a crucial role in combating biological stress. Here, we have characterized a regulatory factor, OsbHLH34, which governs the response of rice to infection by Rhizoctonia solani AG1-IA. The expression of OsbHLH34 significantly impacts the susceptibility of rice to Rhizoctonia solani infection. Through the generation of OsbHLH34 knockout and overexpressing rice plants, we observed that OsbHLH34 acts as a positive regulator of rice resistance against rice sheath blight. The average lesion area of overexpression plants was 14.3%, the average lesion area of wildtype plants was 36%, and the average lesion area of mutant plants was 67.6%. Transcriptome and qRT-PCR analysis showed that OsbHLH34 regulates OsERF34, which is a key transcription factor for ethylene biosynthesis and resistance to sheath blight. By employing yeast one-hybrid and dual luciferase assays, we demonstrated that OsbHLH34 directly interacts with the promoter of OsERF34, thereby activating its transcription. Both in vitro and in vivo experiments confirmed OsERF34 as a direct target of OsbHLH34. These findings not only enhance our understanding of the molecular mechanisms underpinning rice disease resistance but also offer novel targets for the improvement of rice disease resistance through breeding strategies.

Based on the order of the corresponding authors, the following corrections have been made to the original publication [...]

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is a major disease that severely affects safe wheat production. The Huanghuai region plays a vital role in China’s wheat production and the wheat stem rust epidemic across China. However, due to China’s effective control measures, wheat stem rust rarely occurs in the region, resulting in little research on this disease, including the determination of resistance genes in cultivars and elite lines. For this purpose, this study utilized two predominant races (21C3CTHQM and 34MKGQM) of P. graminis f. sp. tritici to determine the resistance levels of 64 wheat cultivars in the Huanghuai wheat region. Additionally, molecular markers linked with Sr24, Sr25, Sr26, Sr31, and Sr38 were used to analyze the presence of these genes. The results indicated that among the 62 wheat cultivars and elite lines, 13 cultivars contained Sr31, four cultivars were detected to contain Sr38, and none contained Sr24, Sr25, or Sr26. Field tests in 2023 showed that three (4.8%) cultivars exhibited immunity to both races, while 20 (32.3%) and 23 (37.1%) cultivars showed resistance to moderate resistance, and 39 (62.9%) and 36 (58.1%) cultivars were moderately susceptible to susceptible. In 2024, one (1.6%) and four (6.5%) cultivars demonstrated immunity to both races, 22 (35.5%) and 23 (37.1%) cultivars showed resistance to moderate resistance, and 39 (62.9%) and 35 (56.5%) cultivars were moderately susceptible to susceptible. With over 50% of the cultivars displaying susceptibility, the overall resistance level was relatively low, indicating that stem rust outbreaks could recur if a sufficient inoculum is present. It is crucial to explore new resistance sources, discover novel resistance genes, and breed wheat cultivars with durable resistance and desirable agronomic traits to enhance the overall resistance to stem rust in Chinese wheat-growing regions.

Wheat stem rust, caused by the fungus Puccinia graminis f. sp. tritici (Pgt), poses a substantial threat to global wheat production. Utilizing stem rust resistance (Sr) genes represents an economically viable, effective, and environmentally friendly approach to disease control. In this study, gene postulation, molecular testing, and pedigree analysis were used to identify the presence of Sr genes in 45 wheat cultivars. In addition, the resistance of these cultivars was evaluated against two predominant Pgt races, 34MRGQM and 21C3CTHTM, at the adult-plant stage during 2021–2022. The results identify seven Sr genes (Sr31, Sr38, Sr30, SrTmp, Sr22, Sr19, and Sr5) within 35 wheat cultivars. Among these, 23 cultivars contained Sr31, whereas Sr5 and SrTmp were present in four cultivars each. Han 5316, Shimai 15, Shiyou 20, and Kenong 1006 exhibited the presence of Sr19, Sr22, Sr30, and Sr38, respectively. Molecular studies confirmed the absence of Sr25 and Sr26 in any of the wheat cultivars. During field evaluation, 37 (82.2%) and 39 (86.7%) wheat cultivars demonstrated resistance to races 34MRGQM and 21C3CTHTM, respectively. Moreover, 33 wheat cultivars (73.3%) exhibited resistance to all the tested races. These study findings will significantly contribute to future research in wheat pre-breeding and abiotic stress tolerance.

Wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a devastating fungal disease that affects wheat globally. The planting of resistant cultivars is the most cost-effective strategy for controlling this disease. The Huanghuai region, as a major wheat-growing area, plays a crucial role in the spread and prevalence of wheat stem rust in China. In this study, 64 wheat accessions from this region were tested at the adult stage against two major Pgt races, 34MKGQM and 21C3CTHQM. DNA markers associated with the known resistance genes Sr31, Sr24, Sr25, Sr26, and Sr38 were measured to determine their presence in the tested accessions. In the 2023 field tests, 5 (7.8%) accessions were immune to 21C3CTHQM and 34MKGQM, while 35 (54.7%) and 39 (60.9%) were moderately resistant and resistant, respectively. The remaining 20 (30.7%) accessions were moderately susceptible and susceptible. In the 2024 tests, 12 (18.8%) and 14 (21.9%) entries were immune to both races; 29 (45.3%) and 30 (46.9%) were moderately resistant and resistant, respectively. Only two cultivars, Xinong 816 and Yimai 211, were immune in both years, and three entries showed some degrees of resistance in both years. Seven cultivars, including Zhongzhimai 23, Longxing 1, Yunong 937, Huaguan 301, Wanke 800, Shaanhe 285, and Yunong 612, showed increased susceptibility. DNA markers showed that 30 entries carried Sr31, while 6 entries carried Sr38. Genes Sr24, Sr25, and Sr26, which confer good resistance to the globally prevalent cultivars TKTTF and TTTRF, were absent from the set of tested entries. While this study surveyed the resistance levels of a cross-section of wheat from the southern part of the Huanghuai region and confirmed the presence of two known resistance genes, the basis of immunity or high levels of resistance in several lines remains obscure.

Wheat stem rust,caused by Puccinia graminis f.sp.tritici(Pgt),is a potentially devastating fungal disease of wheat worldwide.The present study was to evaluate the resistance of 42 wheat monogenic lines with known stem rust resistance(Sr)genes and 69 wheat cultivars to three new Pgt races(34C0MRGQM,34C3MKGQM,and 34C6MTGSM)identified from aeciospores at the seedling and adult-plant stages.The phenotyping results revealed that monogenic lines harboring resistance genes Sr9e,Sr17,Sr21,Sr22,Sr26,Sr30,Sr31,Sr33,Sr35,Sr36,Sr37,Sr38,Sr47,SrTmp,and SrTt3 were effectively resistant to all three Pgt races at the seedling and adult-plant stages.In contrast,monogenic lines containing Sr5,Sr6,Sr7b,Sr9a,Sr9d,Sr9f,Sr9g,Sr9b,Sr16,Sr24,Sr28,and Sr39 were highly susceptible to these races at both seedling and adult-plant stages.The other lines with Sr8a,Sr10,Sr11,Sr13,Sr14,Sr15,Sr18,Sr20,Sr19,Sr23,Sr25,Sr27,Sr29,Sr32,and Sr34,displayed variable levels of resistance to one or two of the tested races.Seedling infection types(ITs)and adult-plant infection responses(IRs)indicated that 41(59.4％)of the wheat cultivars showed high resistance to all the three races.Molecular marker analysis showed that four wheat culitvars likely carried Sr2,20 wheat culitvars likely carried Sr31,9 wheat culitvars likely carried Sr38,and none of the cultivars carried Sr24,Sr25,and Sr26.Our results provide a scientific basis for rational utilization of the tested Sr genes and wheat cultivars against these novel Pgt races.

Wheat stem rust is caused by Puccinia graminis f. sp. tritici. This major disease has been effectively controlled via resistance genes since the 1970s. The appearance and spread of new races of P. graminis f. sp. tritici (eg., Ug99, TKTTF, and TTRTF) have renewed the interest in identifying the resistance gene and breeding cultivars resistant to wheat stem rust. In this study, gene postulation, pedigree analysis, and molecular detection were used to determine the presence of stem rust resistance genes in 65 commercial wheat cultivars from Hebei Province. In addition, two predominant races 21C3CTHTM and 34MRGQM were used to evaluate the resistance of these cultivars at the adult-plant stage in 2021-2022. The results revealed that 6 Sr genes (namely, Sr5, Sr17, Sr24, Sr31, Sr32, Sr38, and SrTmp), either singly or in combination, were identified in 46 wheat cultivars. Overall, 37 wheat cultivars contained Sr31. Sr5 and Sr17 were present in 3 and 3 cultivars, respectively. Gao 5218 strong gluten, Jie 13-Ji 7369, and Kenong 1006 contained Sr24, Sr32, and Sr38, respectively. No wheat cultivar contained Sr25 and Sr26. In total, 50 (76.9%) wheat cultivars were resistant to all tested races of P. graminis f. sp. tritici in field test in 2021-2022. This study is important for breeding wheat cultivars with resistance to stem rust.

为提高药用植物病理学实验课程教学水平、创新教育教学方法、实现实验教学信息化,沈阳农业大学植物保护实验教学中心将数码显微互动系统引入实验教学过程中,不断探索与实践药用植物病理学实验教学新模式.本文介绍了药用植物病理学实验课程的基本情况,分析了传统实验教学现状与不足,探讨了数码显微互动系统的优势及其应用于该课程的模式构建,并分享了取得的教学效果,以期为数码显微互动与农林院校实验教学融合的教育教学方法研究提供参考借鉴.

This is the first study reporting droplet digital PCR and quantitative real time PCR for detection of Tilletia caries (syn. T. tritici), which causes common bunt of wheat and leads to yield losses of 80% in many wheat growing areas worldwide. To establish an accurate, rapid and quantifiable detection method, we tested 100 inter simple sequence repeats (ISSR) primers and obtained a species-specific fragment (515 bp) generated by ISSR 827. Then, a specific 266 bp band for the sequence characterized amplified region (SCAR) marker was produced from T. caries. The detection limit reached 50 pg/μL. Based on the SCAR marker, we further developed a higher sensitivity of quantitative real time-polymerase chain reaction (qRT-PCR) with a detection limit of 2.4 fg/μL, and droplet digital PCR (ddPCR) with a detection limit of 0.24 fg/μL. Both methods greatly improved the detection sensitivity of T. caries, which will be contribute a lot for quickly and accurately detection of T. caries, which causes wheat common bunt.

Summary Wheat stem (or black) rust, caused by Puccinia graminis f. sp. tritici (Pgt), has been historically among the most devastating global fungal diseases of wheat. The recent occurrence and spread of new virulent races such as Ug99 have prompted global efforts to identify and isolate more effective stem rust resistance (Sr) genes. Here, we report the map‐based cloning of the Ug99‐effective SrTm5 gene from diploid wheat Triticum monococcum accession PI 306540 that encodes a typical coiled‐coil nucleotide‐binding leucine‐rich repeat protein. This gene, designated as Sr22b, is a new allele of Sr22 with a rare insertion of a large (13.8‐kb) retrotransposon into its second intron. Biolistic transformation of an ~112‐kb circular bacterial artificial chromosome plasmid carrying Sr22b into the susceptible wheat variety Fielder was sufficient to confer resistance to stem rust. In a survey of 168 wheat genotypes, Sr22b was present only in cultivated T. monococcum subsp. monococcum accessions but absent in all tested tetraploid and hexaploid wheat lines. We developed a diagnostic molecular marker for Sr22b and successfully introgressed a T. monococcum chromosome segment containing this gene into hexaploid wheat to accelerate its deployment and pyramiding with other Sr genes in wheat breeding programmes. Sr22b can be a valuable component of gene pyramids or transgenic cassettes combining different resistance genes to control this devastating disease.

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (an obligate biotrophic pathogen) is a worldwide threat to wheat production that occurs over a wide geographic area in China. For monitoring genetic variation and virulence structure of Blumeria graminis f. sp. tritici in Liaoning, Heilongjiang, and Sichuan in 2015, 31 wheat lines with known Powdery mildew resistance genes and 2 EST-SSR markers were used to characterize the virulence and genetic diversity. Results indicated that 90% of all isolates were virulent on Pm3c , Pm3e , Pm3f , Pm4a , Pm5 , Pm6 (Timgalen), Pm7 , Pm16 , Pm19 , and Pm1 + 2 + 9 and 62.6% to 89.9% of isolates were virulent on Pm3a , Pm3b , Pm3d , Pm4b , Pm6 (Coker747), Pm8 , Pm17 , Pm20 , Pm23 , Pm30 , Pm4 + 8 , Pm5 + 6 , Pm4b + mli , Pm2 + mld , Pm4 + 2X , Pm2 + 6 . The Pm13 and PmXBD genes were effective against most collected isolates from Liaoning and Heilongjiang Provinces. Only Pm21 exhibited an immune infection response to all isolates. Furthermore, closely related isolates within each region were distinguished by cluster analyses using EST-SSR representing some gene exchanges and genetic relationships between the flora in Northeast China (Liaoning, Heilongjiang) and Sichuan. Only 45% of the isolates tested show a clear correlation between EST-SSR genetic polymorphisms and the frequency of virulence gene data. However, the EST-SSR polymorphism of isolated genes did not correspond to the virulence diversity of isolates in the single-gene lineage identification of hosts.

Wheat powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici (Bgt), is a serious disease of wheat worldwide that can cause significant yield losses. Growing resistant cultivars is the most cost-effective and eco-soundly strategy to manage the disease. Therefore, a high breeding priority is to identify genes that can be readily used either singly or in combination for effective resistance to powdery mildew and also in combination with genes for resistance to other diseases. Yunnan Province, with complex and diverse ecological environments and climates, is one of the main wheat growing regions in China. This region provides initial inoculum for starting epidemics of wheat powdery mildew in the region and other regions and thus, plays a key role in the regional and large-scale epidemics of the disease throughout China. The objectives of this study were to evaluate seedling resistance of 69 main wheat cultivars to powdery mildew and to determine the presence of resistance genes Pm3, Pm8, Pm13, Pm16, and Pm21in these cultivars using gene specific DNA markers. Evaluation of 69 wheat cultivars with six Bgt isolates showed that only four cultivars were resistant to all tested isolates, indicating that the overall level of powdery mildew resistance of Yunnan wheat cultivars is inadequate. The molecular marker results showed that 27 cultivars likely have at least one of these genes. Six cultivars were found likely to have Pm3,18 likely to have Pm8,5 likely to have Pm16,and 3 likely to have Pm21. No cultivar was found to carry Pm13. The information on the presence of the Pmresistance genes in Yunnan wheat cultivars can be used in future wheat disease breeding programs. In particular, cultivars carrying Pm21, which is effective against all Bgtraces in China, should be pyramided with other effective genes to developing new cultivars with durable resistance to powdery mildew.

Oat stem rust, caused by Puccinia graminis f. sp. avenae, is one of the most devastating diseases of oat. The most cost-effective and environmentally friendly strategy to control this disease is the use of resistant cultivars. However, P. graminis f. sp. avenae can overcome the resistance of cultivars by rapidly changing its virulence. Thus, information on the virulence of P. graminis f. sp. avenae populations and resistance of cultivars is critical to control the disease. The current study was conducted to monitor the virulence composition and dynamics of the P. graminis f. sp. avenae population in China and to evaluate resistance of oat cultivars. Oat leaves naturally infected by P. graminis f. sp. avenae were collected in 2018 and 2019, and 159 isolates were derived from single uredinia. The isolates were tested on 12 international differential lines, and eight races, TJJ, TBD, TJB, TJD, TJL, TJN, TGD, and TKN, were identified for the first time in China. The predominant race was TJD, virulent against Pg1, Pg2, Pg3, Pg4, Pg8, Pg9, and Pg15, accounting for 35.8 and 37.8% in 2018 and 2019, respectively. The sub-predominant races were TJN (30.2% in 2018, 28.3% in 2019) and TKN (20.8% in 2018, 12.3% in 2019). All isolates were virulent to Pg1, Pg2, Pg3, and Pg4, and avirulent to Pg6 and Pg16. The three predominant races (TJD, TJN, and TKN) were used to evaluate resistance in 30 Chinese oat cultivars at the seedling and adult plant stages. Five cultivars, Bayan 1, Baiyan 2, Baiyan 3, Baiyan 5, and Baiyan 9, were highly resistant to the three races at both seedling and adult plant stages. The results of the virulences and frequencies of P. graminis f. sp. avenae races and the resistant cultivars will be useful in elucidating the pathogen migration and evolution and for breeding oat cultivars with stem rust resistance.

Wheat stem (or black) rust is one of the most devastating fungal diseases, threatening global wheat production. Identification, mapping, and deployment of effective resistance genes are critical to addressing this challenge. In this study, we mapped and characterized one stem rust resistance (Sr) gene from the tetraploid durum wheat variety Kronos (temporary designation SrKN). This gene was mapped on the long arm of chromosome 2B and confers resistance to multiple virulent Pgt races, such as TRTTF and BCCBC. Using a large mapping population (3,366 gametes), we mapped SrKN within a 0.29 cM region flanked by the sequenced-based markers pku4856F2R2 and pku4917F3R3, which corresponds to 5.6- and 7.2-Mb regions in the Svevo and Chinese Spring reference genomes, respectively. Both regions include a cluster of nucleotide binding leucine-repeat (NLR) genes that likely includes the candidate gene. An allelism test failed to detect recombination between SrKN and the previously mapped Sr9e gene. This result, together with the similar seedling resistance responses and resistance profiles, suggested that SrKN and Sr9e may represent the same gene. We introgressed SrKN into common wheat and developed completely linked markers to accelerate its deployment in the wheat breeding programs. SrKN can be a valuable component of transgenic cassettes or gene pyramids that includes multiple resistance genes to control this devastating disease.

新型冠状病毒肺炎疫情期间，在教育部“停课不停教，停课不停学”的号召下，各高校全面开展线上教学。沈阳农业大学植物保护学院在利用网络教学平台开展线上实验教学过程中，将数码显微互动系统引入到线上实验教学，实现了人机互动、远程互动、实时互动，开创了实验教学线上授课新模式，提高了实验教学效果。本文阐述了数码显微互动系统的优势及功能，并重点以《普通植物病理学实验》为例，介绍了数码显微互动系统融合线上实验教学模式实施的具体举措、主要环节以及存在的问题和对策建议等，为突发事件下创建高效的线上实验教学模式提供借鉴。

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, (Pgt) is a devastating disease in wheat production. The disease has been effectively controlled since the 1970s due to the widespread use of the Sr31 resistance gene. However, Sr31 has lost its effectiveness following the emergence and spread of the Ug99 race variants. Therefore, there is an urgent global effort to identify new germplasm resources effective against those races. In this study, the resistance to Pgt of 95 wheat advance lines from Heilongjiang Province was evaluated using three predominant races of Pgt, 21C3CTTTM, 34C0MKGSM, and 34C3MTGQM, in China at the seedling and adult plant stage. The presence of 6 Sr genes (Sr2, Sr24, Sr25, Sr26, Sr31, and Sr38) was evaluated using linked molecular markers. The results showed that 86 (90.5%) wheat lines had plant stage resistance to all three races. Molecular marker analysis showed that 24 wheat lines likely carried Sr38, 15 wheat lines likely carried Sr2, 11 wheat lines likely carried Sr31, while none of the wheat lines carried Sr24, Sr25, or Sr26. Furthermore, six out of the 95 wheat lines tested carried both Sr2 and Sr38, three contained both Sr31 and Sr38, and two wheat lines contained both Sr2 and Sr31. Wheat lines with known Sr genes may be used as donor parents for further breeding programs to provide resistance to stem rust.

《普通植物病理学》课程是植物保护专业本科生一门重要的专业基础课,普及植物病理学基本原理和现代植物病理学基础理念,是培养植物病害专业技术人员的基本知识和基本技能的通识课.为开拓新型教学模式,应用现代化教学技术更好地为学生服务,《普通植物病理学》课程组总结多年教学经验,针对理论教学和实践教学部分进行了线上线下混合式教学的研究,在教学方法和考核方式等方面进行了探索实践.

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is one of the most serious fungal diseases in wheat production, seriously threatening the global supply of wheat and endangering food security. The present study was conducted to evaluate wheat monogenic lines with known Sr genes to the most prevalent P. graminis f. sp. tritici races in China. In addition, wheat lines introduced from the International Maize and Wheat improvement Center (CIMMYT) with resistance to the Ug99 race group were also evaluated with the prevalent Chinese P. graminis f. sp. tritici races. The monogenic lines containing Sr9e, Sr21, Sr26, Sr31, Sr33 , Sr35, Sr37, Sr38, Sr47, and SrTt3 were effective against races 21C3CTTTM, 34C0MRGSM, and 34C3MTGQM at both seedling and adult-plant stages. In contrast, monogenic lines containing Sr6, Sr7b, Sr8a, Sr9a, Sr9b, Sr9d, Sr9f, Sr9g, Sr13, Sr16, Sr18, Sr19, Sr20, Sr24, Sr28, Sr29, and Sr34 were highly susceptible to these races at both seedling and adult-plant stages. Lines with Sr5, Sr10, Sr13, Sr14, Sr15, Sr17, Sr21, Sr22, Sr23, Sr25, Sr27, Sr29, Sr30, Sr32, Sr36, and Sr39 were resistant to one or more of the tested races. Among the 123 CIMMYT lines, 38 (30.9%) showed varying levels of susceptibility to Chinese P. graminis f. sp. tritici races. The results should be useful for breeding wheat cultivars with resistance to stem rust.