Molecular screening of septoria resistance genes in international bread wheat germplasm using the close linked simple sequence repeat (SSR) markers

Abstract

The wheat plant is susceptible to Septoria tritici blotch (STB), a foliar disease caused by Zymoseptoria tritici which significantly reduces crop yield and has developed resistance to synthetic fungicides. Developing resistant wheat cultivars through the identification of the innate immunity is a suitable solution to control this pathogen. Molecular markers are considered a reliable approach for detecting resistant genes in wheat plant compared to conventional methods. This study aimed to employ marker-assisted selection methods utilizing eight SSR markers closed-linked to Stb resistance genes in a collection of 80 international bread wheat germplasm. The results revealed that the genetic frequency of Stb genes ranged from 8 % (Stb2) to 44 % (Stb4), with Stb4 being the most common followed by Stb5 (31 %), Stb3 (26 %), and others. A total of 130 Stb-resistant genes were identified, with Stb4 contributing 27 % of the total. The genotypes such as CItr 8441 (Argentina) and PI 591908 (Australia) harbored up to six Stb genes, while others like ''PI 584985″and PI 584984 (Croatia), did not contained any targeted resistant genes. In short, this study provides valuable insights for breeding resistant wheat cultivars against the Z. Tritici, highlighting the potential and utility of molecular markers in guiding future wheat breeding initiatives.