AAC Perform red spring wheat

AAC Camrose, an awned hard red spring wheat (Triticum aestivum L.) cultivar, combines high grain yield and good agronomic characteristics with excellent resistance to leaf, stripe, and stem rust, Fusarium head blight (FHB) and common bunt. Based on 33 station-years of registration trial data from 2020 to 2022, the grain yield of AAC Camrose was 5% higher than AAC Foray and 11% over AAC Penhold. AAC Camrose was significantly shorter than AAC Foray, had straw strength similar to AAC Penhold and maturity was one day later than AAC Foray. AAC Camrose had similar test weight and protein concentration but lower thousand kernel weight as compared to AAC Foray. AAC Camrose had milling and baking quality suitable for grades of the Canada Prairie Spring Red wheat market class.

Brown, P. D., Randhawa, H. S., Mitchell Fetch, J., Fox, S. L., Humphreys, D. G., Meiklejohn, M., Green, D., Wise, I., Fetch, T., Gilbert, J., McCallum, B. and Menzies, J. 2015. AAC Foray red spring wheat. Can. J. Plant Sci. 95: 799–803. AAC Foray, an orange wheat blossom midge (Sitodiplosis mosellana Géhin) tolerant hard red spring wheat (Triticum aestivum L.), combined high grain yield and good agronomic performance with excellent resistance to leaf and stem rust, and improved resistance to Fusarium head blight. AAC Foray had maturity, straw strength, and test weight similar to the check cultivars. AAC Foray is eligible for grade of the Canada Prairie Spring Red wheat market class.

Leaf rust, caused by Puccinia triticina, is a common and widespread disease of wheat in the US. On an annual basis, over 50 races of the leaf rust fungus are detected. There are at least 5 major groups of genetically distinct P. triticina isolates in the US based on allelic variation at microsatellite loci. Distinct regional race populations of P. triticina are found in the US, due to the widespread use of race-specific leaf rust resistance (Lr) genes in different market classes of wheat. In the south-eastern States where soft red winter wheats are grown, races with virulence to Lr9, Lr11, and Lr18 are predominant. In the southern Great Plains region where hard red winter wheats are grown, races with virulence to genes Lr9, Lr17, Lr24, and Lr26 are common. In the northern Great Plains region where hard red spring wheats are grown, races with virulence to Lr2a and Lr16 are common. Due to the wide dispersal of P. triticina, some races are found in all regions of the US. Highly effective durable resistance to leaf rust has been difficult to achieve due to the high degree of virulence variation in the P. triticina population and the rapid selection of races with virulence to effective Lr genes in wheat cultivars. Hard red spring wheat cultivars with genes Lr16, Lr23, and Lr34 have been highly resistant for more than 10 years in Minnesota and the Dakotas. Stem rust, caused by P. graminis f. sp. tritici, has not been a common disease of wheat in the US since the last major epidemics in the 1950s. The low levels of stem rust infections in the US can be attributed to the increasing use of highly resistant winter and spring wheat cultivars, which has greatly reduced the overall level of stem rust urediniospores. Eradication of the alternate host, Berberis vulgaris, has reduced the number of races and slowed the emergence of new races. Resistance genes Sr2, Sr6, Sr17, Sr24, Sr31, Sr36, and SrTmp are common in the winter wheats. Genes Sr6, Sr9b, Sr11, and Sr17 are common in the spring wheats. Spring wheat cultivars may also have adult plant stem rust resistance derived from cv. Thatcher. Many of the winter and spring wheats are susceptible to the new stem rust race from East Africa; however, cultivars with resistance to this race can be found in each of the major wheat classes.

Stem rust [causal organism: Puccinia graminis f. sp. tritici (Pgt)], stripe rust [Puccinia striiformis f. sp. tritici (Pst)], and leaf rust [Puccinia triticina (Pt)] are important fungal diseases of wheat in Central Asia and worldwide. Therefore, identification of seedling and adult plant resistance (APR) genes is of major importance for the national wheat breeding program in many countries. The objectives of this study were to identify genes that confer seedling and APR resistances in widely grown wheat cultivars, landraces and advanced lines from Tajikistan. A total of 41 wheat accessions were inoculated with eleven races of Pgt, twelve races of Pst and nine races of Pt for postulation of Sr (stem rust), Yr (yellow or stripe rust), and Lr Lr (leaf rust) resistance genes at the seedling stage. In addition, all of the accessions were tested in field trials for the response to stem rust and stripe rust. Genes for seedling stem rust resistance (i.e. Sr5, Sr6, Sr11, Sr31, and Sr38), stripe rust resistance (Yr9, Yr17, and Y27), and leaf rust resistance (Lr16 and Lr26) were postulated in the Tajik wheat. The presence of the pleiotropic APR genes Sr2/Yr30/Lr27 (associated with pseudo-black chaff phenotype) and Lr34/Yr18/Sr57 (associated with leaf tip necrosis phenotype), and also Lr37 were assessed in the field and confirmed with linked molecular markers. In most of the wheat accessions, resistance genes could not be postulated because their infection types did not match the avirulence or virulence profile of the Pgt, Pst and Pt races tested. Six, seven, and nine accessions were identified that likely possess new genes for resistance to stem rust, stripe rust, and leaf rust, respectively, which have not been described previously. The research demonstrates the presence of effective seedling resistance and APR genes in widely grown wheat accessions that could facilitate further rust resistance breeding in the national wheat breeding program in Tajikistan.

BackgroundSecale strictum subsp. africanum, a self-fertile and perennial wild rye species, is endemic to the Roggeveld Mountains of the south-western Karoo, South Africa. Despite historical abundance on the Roggeveld plateau, S. strictum subsp. africanum is currently threatened with extinction. Many reasons have been given for its decline, including susceptibility to rusts. MethodsLeaves with stem, leaf and stripe rust pustules were sampled from cultivated and naturally occurring S. strictum subsp. africanum on the farm Kanariesfontein near Sutherland. Identity of the rust pathogens was determined through infection and sequencing studies. ResultsInoculation studies showed that stem and leaf rust collected from wild rye were avirulent on bread wheat, but virulent on Secale cereale. The stripe rust specimen was virulent on bread wheat and was identified as Puccinia striiformis race 6E16A−. Using ITS sequencing, the wild rye leaf rust specimen was confirmed as Puccinia recondita, and the stripe rust specimen as P. striiformis. ITS sequences did not distinguish between Puccinia graminis f. sp. tritici and Puccinia graminis f. sp. secalis, respectively the causal organisms of wheat and rye stem rust. Inoculation of wild rye plants with P. graminis f. sp. tritici proved its susceptibility to stem rust races attacking wheat and triticale. ConclusionThis study established that S. strictum subsp. africanum is a host for both rye and wheat stem rust, rye leaf rust and wheat stripe rust.

Leaf rust, caused by Puccinia triticina Eriks., is the most common disease of wheat (Triticum aestivum L.) in the United States and worldwide. The objective of this study was to characterize seedling and adult plant leaf rust resistance in hard red spring wheat cultivars grown in Minnesota, North Dakota, and South Dakota, and postulate the identity of the seedling leaf rust resistance genes in the cultivars. Twenty-six cultivars, near-isogenic lines of Thatcher wheat that differ for single leaf rust resistance genes, and three wheat cultivars with known leaf rust resistance genes, were tested with 11 different isolates of leaf rust collected from the United States and Canada. The leaf rust infection types produced on seedling plants of the cultivars in greenhouse tests were compared with the infection types produced by the same isolates on the Thatcher near-isogenic lines to postulate which seedling leaf rust resistance genes were present. Seedling leaf rust resistance genes Lr1, Lr2a, Lr10, Lr16, Lr21, and Lr24 were postulated to be present in spring wheat cultivars. Seedling genes Lr3, Lr14a, and Lr23 likely were present in some cultivars but could not be clearly identified in this study. Most of the cultivars had some level of adult plant leaf rust resistance, most likely due to Lr34. Cultivars that had seedling resistance genes Lr1, Lr2a, Lr10, or Lr16 had poor to intermediate levels of leaf rust resistance in field plots. Cultivars with combinations of seedling resistance genes Lr16 and Lr24 with additional adult plant resistance were highly resistant to leaf rust.

Wheat (Triticum aestivum L.) is an important cereal crop globally as well as in India and yield improvement programs encounter a strong impediment from ever-evolving rust pathogens. Hence, durable rust resistance is always a priority trait for wheat breeders globally. Grain weight, represented as thousand grain weight (TGW), is the most important yield-contributing trait in wheat. In the present study high TGW has been transferred into two elite Indian wheat cultivars PBW343 and PBW550 from a high TGW genotype, Rye selection 111, selected from local germplasm. In the background of PBW343 and PBW550, an increase in TGW upto 27.34 and 18% was observed, respectively (with respect to recipient parents), through conventional backcross breeding with phenotypic selections in 3 years replicated RBD trials. Resistance to leaf rust and stripe rust has been incorporated in the high TGW version of PBW550 through marker assisted pyramiding of stripe rust resistance gene Yr15 using marker Xuhw302, and a pair of linked leaf rust and stripe rust resistance genes Lr57-Yr40 using marker Ta5DS-2754099_kasp23. Improved versions of PBW550 with increased TGW ranging from 45.0 to 46.2 g (up to a 9% increase) and stacked genes for stripe and leaf rust resistance have been developed. This study serves as proof of utilizing conventional breeding and phenotypic selection combined with modern marker assisted selection in improvement of important wheat cultivars as a symbiont of conventional and moderan techniques.

Common or bread wheat (Triticum aestivum L.) is the most important cereal crop in the world, including Kazakhstan, where it is a major agricultural commodity. Fungal pathogens producing leaf, stem, and yellow (stripe) rusts of wheat may cause yield losses of up to 50–60%. One of the most effective methods for preventing these losses is to develop resistant cultivars with high yield potential. This goal can be achieved using complex breeding studies, including the identification of key genetic factors controlling rust disease resistance. In this study, a panel consisting of 215 common wheat cultivars and breeding lines from Kazakhstan, Russia, Europe, USA, Canada, Mexico, and Australia, with a wide range of resistance to leaf rust (LR), stem rust (SR), and yellow rust (YR) diseases, was analyzed under field conditions in Southern Kazakhstan. The collection was genotyped using the 20K Illumina iSelect DNA array, where 11,510 informative single-nucleotide polymorphism markers were selected for further genome-wide association study (GWAS). Evaluation of the phenotypic diversity over 2 years showed a mostly mixed reaction to LR, mixed reaction/moderate susceptibility to SR, and moderate resistance to YR among wheat accessions from Kazakhstan. GWAS revealed 45 marker–trait associations (MTAs), including 23 for LR, 14 for SR, and eight for YR resistances. Three MTAs for LR resistance and one for SR resistance appeared to be novel. The MTAs identified in this work can be used for marker-assisted selection of common wheat in Kazakhstan in breeding new cultivars resistant to LR, SR, and YR diseases. These findings can be helpful for pyramiding genes with favorable alleles in promising cultivars and lines.

Kharouf, Sh., Sh. Hamzeh and M.F. Azmeh. 2021. Races Identification of Wheat Rusts in Syria during the 2019 Growing Season. Arab Journal of Plant Protection, 39(1): 1-13. Wheat rust diseases, caused by Puccinia striiformis f. sp. tritici (stripe or yellow rust), P. triticina f. sp. tritici (leaf or brown rust) and P. graminis f. sp. tritici (stem or black rust) are important factors affecting both durum and bread wheat production in Syria. Considerable losses were caused by these diseases, especially stripe rust, estimated at more than one million metric tons, in the 2010 season, out of 5 million anticipated production. Therefore, it is essential to monitor and follow the movement of these three rust physiological races. In the 2019 growing season, 165 wheat fields were surveyed, and 312 samples were collected and characterized. Ten races of stripe rust were identified in ten locations, of which, four represent new record in Syria, namely the races 16E154, 69E150, 264E46 and 258E64. In addition, four races of leaf rust were identified in four locations, one of which (BKLP) is a new record in Syria. In addition, three previously recorded stem rust races were identified from three different locations. It should be mentioned that the newly recorded races of stripe rust are able to overcome resistance genes Yr1 and Yr5, on which the resistance of durum wheat cultivars such as "Cham3" depended, with a disease severity of 40S recorded in the same locations. It is also worth noting that the stripe rust race 462E128 (warrior) was not detected in the isolates studied. Likewise, the stem rust race Ug99 was also not identified, and because of the aggressiveness of this race, continuous inspection through field surveys accompanied with pathogenicity tests is essential during the coming seasons. Keywords: Stripe (yellow) rust, Leaf (brown) rust, stem (black) rust, race identification, wheat, Syria

In the Republic of Tatarstan, common spring wheat (Triticum aestivum L.) occupies a leading position in crop rotations and is sown annually on more than 400,000 hectares. Diseases caused by the phytopathogen Puccinia striiformis, which can reduce yields by up to 90 %, are a particular threat to wheat crops. In our work, 25 breeding cultivars of soft spring wheat bred by the Tatar Scientific Research Institute of Agriculture were genotyping for yellow rust resistance genes – Yr1 (gwm311), Yr5 (S23M41 and S19M93), Yr10 (Xpsp3000), Yr15 (Xgwm413) and Yr17/Lr37/Sr38 (Ventriup/LN2). The presence of the Yr5-associated marker S23M41 in the genotype was detected in 56 % of the tested cultivars. The S19M93 marker was identified in 84 % of the studied cultivars. The presence of the Xgwm413 marker was detected in 32 % of the tested spring wheat varieties. Negative results were obtained for the identification of the molecular marker Ventriup/LN2 associated with genes for resistance to stripe, leaf and stem rust in all the studied cultivars. The results obtained indicate the genetic diversity of these cultivars with regard to resistance to P. striiformis. The presence of three yellow rust resistance genes (Yr1, Y5 and Yr15) was detected for ‘Barakat’, ‘Yoldyz’, ‘Kazanskaya Yubileynaya’, ‘Sitara’, ‘Ekada 113’ and ‘Ekada 214’.

Several tests were done in bread wheat (Triticum aestivum L.) to demonstrate the occurrence of genes on D-genome chromosomes that suppress resistance to leaf rust (Puccinia recondita f. sp. tritici Rob. ex Desm.) and stem rust (Puccinia graminis f. sp. tritici Eriks. &Henn.). Ten rust-resistant wild tetraploid wheats (T. turgidum var. dicoccoides) were crossed with both durum (T. turgidum var. durum) and bread wheats. In all cases, resistance to leaf rust and stem rust was expressed in the hybrids with durum wheats but suppressed in the hybrids with bread wheats. Crosses were made between five diverse durum wheats and four diverse bread wheats. The pentaploid hybrid seedlings of 12 crosses were tested with leaf rust race 15 and in all cases the resistance of the durum parents was suppressed. Fourteen D-genome disomic chromosome substitution lines in the durum wheat 'Langdon' were tested with stem rust race 15B-1 and leaf rust race 15. Chromosomes 1B, 2B, and 7B were found to carry genes for resistance to stem rust but no suppressors were detected. Chromosomes 2B and 4B carried genes for resistance to leaf rust, and 1D and 3D carried suppressors. Crosses between seven D-genome monosomies of 'Chinese Spring' and three dicoccoides accessions showed that 'Chinese Spring' possesses genes on 1D, 2D, and 4D, which suppress the stem rust resistance of all three dicoccoides accessions. All three chromosomes must be present to suppress resistance, indicating that some form of complementary gene interaction is involved. In addition, 'Chinese Spring' carries a gene or genes on 3D that suppresses the leaf rust resistance of all three dicoccoides accessions, plus a gene or genes on 1D that suppresses the leaf rust resistance of only one of them. The data raise some interesting questions about the specificity of the suppressors. The high frequency of occurrence of suppressors in the bread wheat population suggests that they must have a selective advantage.Key words: Triticum aestivum, stem rust, leaf rust, rust resistance, suppressor.

Leaf rust, stem rust, and stripe rust are among the most important diseases of wheat and barley worldwide and are best controlled using genetic resistance. To increase the diversity of rust resistance in wheat and barley, a project was initiated to identify and characterise rust resistance genes from the wild species of Aegilops sharonensis (Sharon goatgrass) and Hordeum vulgare ssp. spontaneum (wild barley), respectively. One hundred and two accessions of Sharon goatgrass from Israel and 318 Wild Barley Diversity Collection (WBDC) accessions from the Fertile Crescent, Central Asia, North Africa, and the Caucasus region were evaluated for resistance to leaf rust, stem rust, and/or stripe rust. Sharon goatgrass exhibited a wide range of infection types (ITs) in response to leaf rust, stem rust, and stripe rust. The percentage of resistant accessions in Sharon goatgrass was 58.8–78.4% for leaf rust, 11.8–69.6% for stem rust, and 46.1% for stripe rust, depending on the race used and the plant growth stage. Genetic studies with Sharon goatgrass revealed oligogenic resistance to leaf rust and stem rust. Wild barley also exhibited a wide range of ITs to leaf rust and stem rust; however, the overall frequency of resistance was lower than for Sharon goatgrass. The percentage of resistant accessions in wild barley was 25.8% for leaf rust and 5.7–20.1% for stem rust, depending on the race used. Resistance to the new virulent stem rust race TTKS (i.e. Ug99), present in eastern Africa, was found in both Sharon goatgrass (70% of accessions) and wild barley (25% of 20 accessions tested). Association mapping for stem rust resistance was applied in the WBDC using Diversity Arrays Technology (DArT) markers. Using the highly conservative P value threshold of 0.001, 14 and 15 significant marker associations were detected when the number of subpopulations (K value) was set for 10 and 8, respectively. These significant associations were in 9 and 8 unique chromosome bins, respectively. Two significant marker associations were detected for resistance to the wheat stem rust race MCCF in the same bin as the rpg4/Rpg5 complex on chromosome 7(5H). The presence of a major stem rust resistance gene in this bin on chromosome 7(5H) was validated in a bi-parental mapping population (WBDC accession Damon × cv. Harrington) constructed with DArT markers. The results from this study indicate that Sharon goatgrass and wild barley are rich sources of rust resistance genes for cultivated wheat and barley improvement, respectively, and that association mapping may be useful for positioning disease resistance genes in wild barley.

Stripe rust and leaf rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss. and P. triticina, respectively, are devastating fungal diseases of common wheat (Triticum aestivum L.). Chinese wheat cultivar Bainong 64 has maintained acceptable adult-plant resistance (APR) to stripe rust, leaf rust and powdery mildew for more than 10years. The aim of this study was to identify quantitative trait loci/locus (QTL) for resistance to the two rusts in a population of 179 doubled haploid (DH) lines derived from Bainong 64×Jingshuang 16. The DH lines were planted in randomized complete blocks with three replicates at four locations. Stripe rust tests were conducted using a mixture of currently prevalent P. striiformis races, and leaf rust tests were performed with P. triticina race THTT. Leaf rust severities were scored two or three times, whereas maximum disease severities (MDS) were recorded for stripe rust. Using bulked segregant analysis (BSA) and simple sequence repeat (SSR) markers, five independent loci for APR to two rusts were detected. The QTL on chromosomes 1BL and 6BS contributed by Bainong 64 conferred resistance to both diseases. The loci identified on chromosomes 7AS and 4DL had minor effects on stripe rust response, whereas another locus, close to the centromere on chromosome 6BS, had a significant effect only on leaf rust response. The loci located on chromosomes 1BL and 4DL also had significant effects on powdery mildew response. These were located at the same positions as the Yr29/Lr46 and Yr46/Lr67 genes, respectively. The multiple disease resistance locus for APR on chromosome 6BS appears to be new. All three genes and their closely linked molecular markers could be used in breeding wheat cultivars with durable resistance to multiple diseases.

Stripe rust (Puccinia striiformis f. sp. tritici) and leaf rust (Puccinia triticina) can cause significant yield reductions to hard red spring wheat (HRSW) in North Dakota (ND). The use of host resistance and fungicides can successfully manage this disease. However, the combination of them may not be appropriate every year. From 2016 to 2018, fungicide timing by cultivar experiments were conducted to update recommendations for rust management. Experiments were designed in a randomized complete block with a split-plot arrangement. Main plots included three HRSW cultivars that were moderately resistant, moderately susceptible, and susceptible. Subplots included the fungicide timings of Feekes 9, Feekes 10.5.1, a sequential application, and a nontreated control. Field experiments were categorized into three environments depending on rust onset and disease progress. When rust was detected at early heading, the susceptible cultivar benefited from all fungicide application timings. The detection of rust at tillering leaf stages suggested that fungicide treatments statistically lowered disease and in most cases had statistically higher yield, regardless of host resistance. These results suggest that the benefit from a fungicide application to manage leaf rust and stripe rust is highly influenced by the timing of disease onset and level of host resistance. Results will improve fungicide suggestions for HRSW producers in ND.

Wheat rusts, produced by three species of Puccinia, are severe diseases and important biotic impediments in efforts to keep wheat production going around the world.The most commercially significant and prevalent diseases among global wheat varieties includes leaf rust also known as brown rust, caused by Puccinia graminis triticina Eriks, stem or black rust caused by Puccinia graminis f. sp. tritici, and stripe or yellow rust caused by Puccinia striiformis f. Tritici.Currently,more than 200 rust resistance genes (100 leaf rust, 60 stem rust, and 51 stripe rust) have been identified by using various molecular approaches from several wheat crop species and related wild species. This review highlights various aspects of Lr (Leaf rust), Sr (Stem rust) and Yr(yellow rust) resistance genes, their primitive origins, and their prevalence in globally wheat cultivars.