GENETIC ASSESSMENT AND BREEDING OF BREAD WHEAT FOR RESISTANCE TO COMMON BUNT (TILLETIA CARIES AND T. LEVIS) IN UZBEKISTAN

Common bunt (Tilletia caries and T. levis) remains a major biotic constraint in winter wheat cultivation under rainfed conditions in Uzbekistan, causing significant yield losses. This study aimed to identify and evaluate sources of genetic resistance to common bunt in bread wheat using artificial inoculation and field surveys conducted between 1988 and 2010. A total of 1,255 wheat accessions from diverse geographic origins were screened, with only 20 accessions demonstrating complete immunity. Monogenic lines carrying Bt5, Bt6, and Bt9 genes showed high resistance levels, while multigenic lines (Bt1, Bt2, Bt4, Bt7) were highly susceptible under local pathogen pressure. Genetic analysis of F₂ hybrids revealed Mendelian segregation patterns, indicating the presence of one or two recessive resistance genes. Crosses between resistant donors and susceptible testers confirmed the inheritance and potential of these genes in breeding programs. Selected immune accessions—especially those combining early maturity and high productivity—are recommended as effective donors for the development of common bunt-resistant wheat cultivars adapted to the Uzbek agro-climatic context.