Genetic Variation in Turkish Bread Wheat (Triticum aestivum L.) Varieties for Resistance to Common Bunt

Common bunt, caused by Tilletia laevis and T. caries, is one of the major wheat diseases in Turkiye and in many countries in the world. To control this disease, chemical seed treatment is commonly used; however, it may cause harm to human and environmental health. Therefore, genetic resistance to control common bunt in an environmentally friendly, cost-effective, and sustainable manner is the best choice. This study was conducted to determine the reactions of 102 bread wheat (Triticum aestivum L.) varieties with regard to their resistance to common bunt in field conditions over three consecutive years. Additionally, these varieties were molecularly screened with linked markers to Bt8, Bt9, Bt10, and Bt11. The infection rates ranged from 3.17 to 91.49%, 5.41 to 91.41%, 5.29 to 94.06%, and 6.85 to 90.30% in the growing seasons 2019-2020, 2020-2021, and 2021-2022 and overall, respectively. In molecular screening, Bt8 was detected in 2 of the varieties, Bt10 in 10 of them, and Bt11 in 15 of them. There was no variety carrying only Bt9. However, many gene combinations, such as Bt8 + Bt9, Bt8 + Bt11, Bt9 + Bt10, Bt9 + Bt11, Bt8 + Bt9 + Bt10, and Bt8 + Bt9 + Bt11, were determined. The varieties with a gene combination of Bt8 + Bt9 + Bt11 had the lowest infection rates. As a result, 65.68% of the varieties were very susceptible. Only 3.92% of them had moderately resistant reaction. These varieties could be used in breeding programs conducted for resistance to common bunt.