Genetic Variation in Common Bunt Resistance in Synthetic Hexaploid Wheat

Common bunt (caused by Tilletia caries and T. Foetida) is a major wheat disease. It occurs frequently in the USA and Turkey and damages grain yield and quality. Seed treatment with fungicides is an effective method to control this disease. However, using fungicides in organic and low-income fields is forbidden, and planting resistant cultivars are preferred. Due to the highly effective use of fungicides, little effort has been put into breeding resistant genotypes. In addition, the genetic diversity for this trait is low in modern wheat germplasm. Synthetic wheat genotypes were reported as an effective source to increase the diversity in wheat germplasm. Therefore, a set of 25 synthetics that are resistant to the Turkish common bunt race were evaluated against the Nebraska common bunt race. Four genotypes were found to be very resistant to Nebraska's common bunt race. Using differential lines, four isolines carrying genes, Bt10, Bt11, Bt12, and Btp, were found to provide resistance against both Turkish and Nebraska common bunt races. Genotypes carrying any or all of these four genes could be used as a source of resistance in both countries. No correlation was found between common bunt resistance and some agronomic traits, which suggests that common bunt resistance is an independent trait.

Automated summary

Common bunt is a major wheat disease that causes significant damage to grain yield and quality in the USA and Turkey. Although seed treatment with fungicides is an effective control method, it is forbidden in organic and low-income fields, leading to a preference for planting resistant cultivars. The use of fungicides has resulted in limited efforts to breed resistant genotypes, and the genetic diversity for this trait is low in modern wheat germplasm. However, synthetic wheat genotypes have been found to be an effective source of increasing diversity in wheat germplasm.