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The stem, black and cereal rusts are caused by the fungus ''Puccinia graminis'' and are a significant disease affecting cereal crops. Crop species which are affected by the disease include bread wheat, durum wheat, barley and triticale.〔 An epidemic of stem rust on wheat caused by race TTKSK (e.g. isolate Ug99) is currently spreading across Africa, Asia and the Middle East and is causing major concern due to the large numbers of people dependent on wheat for sustenance. The strain was named after the country where it was identified (Uganda) and the year of its discovery (1999).〔 It spread to Kenya, then Ethiopia, Sudan and Yemen, and is becoming more virulent as it spreads.〔 Scientists are working on breeding strains of wheat that are resistant to UG99. However, wheat is grown in a broad range of environments. This means that breeding programs would have extensive work remaining to get resistance into regionally adapted germplasms even after resistance is identified.〔 == Biology == There is considerable genetic diversity within the species ''P. graminis'', and several special forms, ''forma specialis'', which vary in host range have been identified. * ''Puccinia graminis f. sp. avenae'', oat * ''Puccinia graminis f. sp. dactylis'' * ''Puccinia graminis f. sp. hordei'', barley * ''Puccinia graminis f. sp. lolii'' * ''Puccinia graminis f. sp. poae'' * ''Puccinia graminis f. sp. secalis'', rye, barley * ''Puccinia graminis f. sp. tritici'', wheat, barley ''P. graminis'' is a member of the phylum Basidiomycota within the kingdom Fungi. The characteristic rust color on stems and leaves is typical of a general stem rust as well as any variation of this type of fungus. Different from most fungi, the rust variations have five spore stages and alternate between two hosts. Wheat is the primary host, and barberry is the alternate host. There are multiple pathotypes (including QCC and MCC) affecting barley, within ''forma specialis tritici''.〔Jin, Y; Steffenson, Bj; Miller, Jd, 1994: "Inheritance of resistance to pathotypes QCC and MCC of ''Puccinia graminis'' f.sp. ''tritici'' in barley line Q21861 and temperature effects on the expression of resistance". ''Phytopathology'' 84(5): 452-455〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「stem rust」の詳細全文を読む スポンサード リンク
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