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New strain ofstem rust on wheat in Kenya

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Publish time: 4th February, 2015      Source: A ProMED-mail post<http://www.cnchemicals.com/;
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New strain ofstem rust on wheat in KenyaNew strain ofstem rust on wheat in Kenya" title="Share this link on Facebook">A ProMED-mail post<http://www.cnchemicals.com/;ProMED-mail is a program of theInternational Society for Infectious Diseases <http://www.isid.org>Date: Fri 30 Jan 2015Source: CIMMYT (International Maize and Wheat Improvement Centre) [edited] <http://www.cimmyt.org/en/what-we-do/wheat-research/item/wheat-farmers-in-kenya-battle-new-race-of-stem-rust-disease>The disease resistant "Robin" wheat variety was struck by a new strain of stem rust. Wheat is the 2nd most important crop in Kenya after maize. The stem rust that destroyed [the] crops [is considered] a sister strain of the dangerous Ug99. Robin variety [was] developed at CIMMYT. It's a hardy variety, said Sridhar Bhavani, who heads the CIMMYT stem-rust screening nurseries in East Africa."We've been racing to try and combat stem rust by breeding wheat varieties that contain resistance genes. The temporary solution is to spray fungicide," he said. "[Some farmers] lost [their] crops because [they were] not aware of the new race. Timely application of fungicides can ensure a crop is protected. Large-scale farmers can invest in enough spray, but small scale farmers may lose their crops because they are resource poor."Ug99 [group strains] have so far been detected in Ethiopia, Eritrea, Iran, Kenya, Mozambique, Rwanda, South Africa, Sudan, Tanzania, Uganda, Yemen and Zimbabwe. The major fear is the potential impact of Ug99 if it spreads into the Asian breadbasket of India and China."The migration of this disease across geographical borders indicates it can affect food security on a global scale," said Bhavani. "We've now identified 8 variants within the Ug99 lineage throughout Africa, showing that Ug99 has a complex virulence to several genes."International scientists working under the Borlaug Global Rust Initiative have developed and released 45 resistant wheat varieties.Most vulnerable countries have protectively produced Ug99 resistant varieties on at least 5 percent of their wheat-growing area.[byline: Julie Mollins]--communicated by:ProMED-mail<promed@promedmail.org>[Wheat stem rust is caused by the fungus _Puccinia graminis_. Overall yield losses of up to 80 per cent are reported, but some fields are totally destroyed. Stem rust spores are spread by wind and with infected straw. Some grasses or volunteer wheat may generate a "green bridge" providing inoculum for the next cropping season. Disease management may include fungicide applications, control of volunteer wheat and resistant varieties if available.New races are emerging, including Ug99 group strains, which have overcome the major resistance gene Sr31 used in current wheat varieties. Ug99 resistant wheat varieties containing different resistance genes have been developed, such as Robin (resistance genesSr2 and SrTmp), which has been widely planted in Kenya for the last few years. Unfortunately, its stem rust resistance has now broken down. The new fungal strain apparently still needs to be characterised to determine whether it belongs to the Ug99 group.MapsKenya:<http://www.ogiek.org/photo-gallery/kenya-map-big.jpg>Africa, Europe and Middle East, overview:<http://worldatlas.com/webimage/countrys/africa/maps/africa.htm>PicturesStem rust symptoms on wheat:<http://www.ars.usda.gov/images/docs/9910_10104/stemrust_inset.jpg>and<http://www.irinnews.org/PhotoDetail.aspx?ImageId=201010281134020344>(Ug99)Effects of Ug99 on resistant and susceptible wheat cultivars:<http://www.irinnews.org/PhotoDetail.aspx?ImageId=201010281129340750>LinksInformation on wheat stem rust:<http://www.ars.usda.gov/Main/docs.htm?docid=9910>Information on Ug99:<http://www.ars.usda.gov/Main/docs.htm?docid=14649>,<http://www.pestalert.org/viewNewsAlert.cfm?naid=36> and <http://www.agbioworld.org/newsletter_wm/index.php?caseid=archive&newsid=2686>Stem rust race nomenclature:<http://www.fao.org/agriculture/crops/rust/stem/stem-pathotypetracker/stem-racenomenclature/en/>_P. graminis_ taxonomy and synonyms:<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=159822>and<http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=159822>Stem rust strains currently present in Kenya:<http://rusttracker.cimmyt.org/?page_id=643>Updates of worldwide distribution of stem rust strains via:<http://rusttracker.cimmyt.org/>Information on Robin wheat variety:<http://wheatatlas.org/varieties/detail/25737> and <http://www.trust.org/item/20131030112148-c27df/>Global Rust Initiative:<http://www.globalrust.org/>CIMMYT:<http://www.cimmyt.org/en/> - Mod.DHAA HealthMap/ProMED-mail map can be accessed at:<http://healthmap.org/promed/p/174>.][See Also:2014---Stem rust, wheat - Germany: strains 20140404.2379670 Stem rust, wheat - Ethiopia (02): strains 20140327.2360315 Stem rust, wheat - Ethiopia: (southern) alert 20140109.21627582012---Stem & stripe rusts, wheat: double resistance breeding20120831.1274190Stem rust, wheat - Africa: new races 20120607.11590762011---Wheat stem rust, Ug99 group - Zimbabwe, Mozambique: new races20110824.25742010---Wheat stem rust, Ug99 - Kenya: (RV), update 20101103.3976 Wheat stem rust, Ug99 group: new races 20100602.18342009---Stem rust, wheat - India: new strain 20090717.2548 Wheat stem rust, strain Ug99: resistance breeding 20090326.1168 Wheat rusts - Kenya, India, Australia 20090312.10192008---Wheat stem rust Ug99 - Australia ex Ethiopia: interception20081203.3807Wheat stem rust, strain Ug99 - multicountry: update 20081120.3660 Wheat stem rust, strain Ug99 - Iran: 1st rep, alert 20080307.0925]More news from: ISID (International Society for Infectious Diseases)Website: http://www.isid.orgPublished: February 4, 2015The news item on this page is copyright by the organization where it originatedFair use notice