Seeking to achieve effective selection against yellow rust resistance in wheat (Triticum aestivum L.) was the aim of this study. Five populations (P₁, P₂, F₁, F₂, and F₃), upon development from seven cross combinations of wheat, underwent evaluation using a randomized complete block design at two locations, i.e., Agricultural Research Institute, D.I. Khan, and Cereal Crops Research Institute, Pirsabak, Nowshera, Pakistan. Phenotypic study of the generations revealed significant variations were evident among all cross combinations, except RK-23 × Seher and RK-23 × Zincol. The majority of the crosses manifested notable generation × location interaction for all yellow rust traits, except RK-23 × Zincol. The highest means for response value (0.93), rust severity (56.8%), and coefficient of infection (46.5) of yellow rust resulted in Inqilab and its derived generations (F₁–F₃) in the cross RK-23 × Inqilab. Meanwhile, the lowest values (0) were noticeable in Shahkar and in its derived population, RK-23 × Shahkar. Molecular study indicated the presence of Yr15, Yr17, and Yr18 genes in selected F₃ lines of RK-23 × Zincol, RK-23 × Shahkar, and RK-23 × Borlaug. Based on the phenotypic and molecular performance of the populations of RK-23 × Zincol, RK-23 × Shahkar, and RK-23 × Borlaug, they emerged as resistant to yellow rust.

Keywords: Wheat (T. aestivum L.), segregating populations, yellow rust, genotype-by-environment interactions, generation means, Yr markers, MAS

Key findings: Wheat (T. aestivum L.) cultivars Shahkar, Zincol, and Borlaug in cross combination with RK-23 produced the rust-resistant genotypes in F₂ and F₃ generations, and the same also have successful confirmation through molecular study. Therefore, these cross combinations could further entail exploration in future wheat breeding for rust resistance.