Plant Biotechnology & Agriculture

Marker-assisted breeding is defined as the application of molecular markers in combination with linkage maps and genomics, to alter and improve plant traits on the basis of genotypic assays. Yellow rust, caused by Puccinia striiformis f.sp. tritici, is one of the major devastating factors worldwide in common wheat (Triticum aestivum L.). It is vital to identify associated DNA markers for Yr

genes that can be used for marker assisted selection in wheat breeding programs to develop new cultivars with higher resistance. Here we report on the identification of six polymerase chain reaction (PCR)-based DNA markers (Xgwm382, Xgwm311, wmc658, PK54, BU099658, C6) linked with yellow rust resistance. Another issue requiring marker-assisted breeding are resistance for Plasmopara halstedii responsible for downy mildew disease and Orobanche cumana, holoparasitic plant called as sunflower broomrape, lead to

loss of yield discount up to 100%. Single nucleotide polymorphism (SNP) markers linked with Pl8, Pl13 and Plarg resistance genes for downy mildew disease in combination with competitive allele specific PCR (KASP) assay which is a fluorescent tagged allele specific PCR method that is more efficient way to determine SNPs like insertions and deletions than other PCR techniques were identified. SNP markers (NSA2220 and NSA2251 for Pl8 gene, NSA0052 and NSA0354 for Pl13 gene, NSA2867 and NSA6138 for Plarg gene) were found discriminative among resistant and susceptible parents and their F2 populations. Also, evaluation of O. cumana races by KASP assay has been performed and SNP197 marker converted from the one SSR marker (Ocum-197), was found as a distinctive marker for O. cumana races. All these efforts mentioned above show the potential use and power of PCR-based and sequence-based DNA markers in plant breeding programs particularly for disease resistance in wheat and sunflower.