Molecular mapping of leaf rust resistance gene LrG98 in Chinese wheat line Guizhou 98-18.

Wheat line Guizhou 98-18 showed low infection types to most of Chinese current isolates of Puccinia triticina.Resistance gene postulation suggested that Guizhou 98-18 might carry a new leaf rust resistance gene.In order to make use of the new leaf rust resistance gene effectively,F1 and F2 populations from the cross Guizhou 98-18/Zhengzhou 5389 were tested with prevalent Chinese pathotype THTT in greenhouse.The results indicated that Guizhou 98-18 carried a single dominant resistance gene,temporarily designated LrG98.A total of 1 274 SSR and STS primers were selected to test the two parents,as well as resistant and susceptible bulks.Four polymorphic markers on chromosome 1BL were used to test genotype F2 plants.Subsequent lin-kage analysis indicated that the resistance gene LrG98 was linked to SSR marker Xbarc582-1B and STS marker of Lr26 with genetic distances of 3.8 cM,respectively.The seedling reaction pattern of LrG98 was different from those of lines with Lr26,Lr33,Lr44 and LrZH84,all of which were located in chromosome 1B.It was concluded that LrG98 was likely to be a new leaf rust resistance gene.