WHEAT Triticum L.) CULTIVARS FROM GRIN COLLECTION (USA) SELECTED FOR DURABLE RESISTANCE TO Septoria tritici AND Stagonospora nodorum BLOTCH
Bibliographic record
Abstract
Septoria tritici blotch (STB) or Stagonospora nodorum blotch (SNB) are among the most harmful and economically significant diseases of wheat in the grain growing regions of the world, especially in the countries with a temperate climate. In epiphytotic years the losses from the disease can reach 30-40 %. In Russia the diseases holds a dominant position in a pathogenic complex of fungus diseases of grain crops. In this paper we first determined the parameters of partial resistance in the cultivars of wheat (genus Triticum) from the collection of the Germplasm Resources Information Network (GRIN, USA) using the stable strains of Septoria tritici and Stagonospora nodorum pathogens. The aim of our study was to select wheat varieties with long-term resistance to blotch based on field and laboratory tests. A long-term study (2009)(2010)(2011)(2012)(2013)(2014)(2015) of the disease development on the wheat cultivars from GRIN Collection were conducted at artificial infection in infection nursery (Central region of Russia, Moscow Province). The samples studied belonged to various genetic groups. A total of 20 samples were diploids (2n = 14), 409 samples were tetraploids (2n = 28), 1688 samples were hexaploids (2n = 42), and also 397 lines derived from crossing of Triticum aestivum with Aegilotriticum were tested. The area under disease progress curve was determined, and the index of resistance (IR) was calculated. The cultivars, that characterized by slow development of the disease in the field, i.e. with high-and middle IR, were selected for laboratory studies. The plants were grown in artificial climate chambers till the 3 rd leaf fully unfolded. Pieces of leaves were inoculated by a drop of spore suspension of S. tritici (4 isolates) or St. nodorum (4 isolates), 10 replications per each variety-topathotype combination. The samples were grouped according to the latent period length and size of infectious spots. As a result, 191 samples of T. aestivum subsp. aestivum and a sample of T. aestivum subsp. spelta with a high index of resistance to the disease were selected among hexaploid wheat; 16 samples were found in tetraploid wheat, including 8 samples of T. turgidum subsp. durum, 2 samples of T. turgidum subsp. turgidum, 3 samples of T. turgidum subsp. dicoccon, 3 samples of T. timopheevii subsp. timopheevii; and 4 samples were selected from diploid wheat T. monococcum subsp. aegilopoides. Eleven lines derived from crossing of T. aestivum and Aegilotriticum sp. showed the sloweddown in the disease development. The selected hexaploid wheat cultivars were mostly from North American ecology-geographical group of T. aestivum subsp. aestivum, including 77 cultivars from the USA and 18 -from Canada (34.5 % in total). Selected tetraploid wheat samples of T. turgidum subsp. durum were from North and Central America, and those of T. turgidum subsp. turgidum, T. timopheevii subsp. timopheevii and T. turgidum subsp. dicoccon from Europe and Asia. The samples from Iraq and Hungary with a high index of blotch resistance were found among diploid wheat T. monococcum subsp. aegilopoides. The synthetic lines of wheat from the USA and Mexico were also characterized by a slowed-down development of the disease. Thus the wheat cultivars with partial resistance have been revealed, including 10 cultivars with partial resistance to Septoria tritici blotch and 40 cultivars -to Stagonospora nodorum blotch.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".