The present invention relates to screening methods for rust resistance or tolerance, in particular, Asian soybean rust (ASR—Phakopsora pachyrhizi). In addition, the present invention relates to the use of molecular markers for the Glycine genus, in particular, for the Glycine max species. The present invention further relates to a method for identifying loci with quantitative and/or qualitative traits associated with rust resistance or tolerance in plants by means of molecular markers. Said markers can be used for assisted screening in improvement programs directed to selecting disease-resistant or -tolerant plants. The present invention also relates to gene pyramiding related to rust resistance. The markers of the present invention are also useful for the positional cloning of rust-resistant or -tolerant genes. Also disclosed are a method for obtaining disease-resistant or -tolerant cultivars, a process for obtaining a plant population and a method for controlling diseases in a plant population. Another object of the present invention is the use of species from the Glycine genus as a source of resistance for obtaining ASR-resistant or tolerant cultivars.