Stripe (yellow) rust, caused by Puccinia striiformis f. sp. tritici (Pst), is among the most important foliar diseases of wheat,
posing a persistent threat to the production of such a strategic crop in many regions worldwide. In 1993 alone, the damage caused by stripe rust in Iran was estimated at 1.5 million tons, representing approximately 15% of total wheat production during that period. Despite having a positive effect on controlling the yellow rust disease, application of fungicides pose many economic costs and environmental issues. To this end, the use of disease-resistant cultivars is known as the most reliable and cost-effective way to prevent the damage inflicted by P. striiformis. By using different resistant cultivars and reducing the life cycles of P. striiformis, the casual agent of strip rust disease, the genetic diversity of such a disease can be effectively reduced. To date, 80 resistance genes against yellow rust have been identified, among which Yr5 and Yr15 stand out as highly effective and durable genes conferring whole-plant resistance. Yr5 and Yr15 are recognized as durable resistance genes, whereas the resistance conferred by other genes has been overcome in the past. Pyramiding such genes can be an effective approach to improve resistant cultivars to yellow rust disease. Marker-assisted selection (MAS), a revolutionary approach, has demonstrated that breeders can directly select alleles without relying on phenotypic evaluation.
Although it never replaced phenotype and conventional selection methods, MAS currently plays an important role in
introgression through backcrossing, gene pyramiding, and line development in wheat breeding programs. The aim of this
research was to introduce two durable yellow rust resistance genes, Yr5 and Yr15, to six Iranian cultivars using markerassisted backcrossing