Genetics of resistance to Septoria tritici blotch (Mycosphaerella graminicola)

摘要

Septoria tritici blotch is the major foliar disease of wheat in many parts of the world. Lack of knowledge about the genetics of resistance to septoria has been a major constraint on breeding. We have used cytogenetics and molecular markers to locategenes for resistance to septoria. Analysis of inter-varietal chromosome substitution lines, including the use of microsatellite markers to validate these lines, showed that Bezostaya 1 chromosome 3A, substituted into either Hobbit sib or Cappelle Desprez, carries specific resistance to isolate IP0323. This is probably controlled by the gene Stb6. Chromosomes 4A of Cappelle Desprez and 5BS-7BS of Hobbit sib appear to carry genes for partial resistance to septoria. In previous work on Synthetic 6x, a specific resistance gene to isolate IP094269 was located near the centromere of chromosome 7D and named Stb5. Further work involving pathology tests and microsatellite mapping, is now under way to test whether resistance to six other isolates is controlled by Stb5 or by a cluster of closely linked resistance genes. The resistance of Triticum macha to septoria tritici blotch included both isolate-specific and non-specific components. The specific resistance appears to be the Stb6 gene plus additional specific resistance genes currently under investigation.