Molecular markers are now in common use, particularly where diagnostic markers (i.e. allele-based functional markers or closely linked markers) exist. Diagnostic markers have been identified for a range of traits, particularly for qualitatively inherited disease resistance, in diverse crop plants. While several studies have been undertaken on mapping Quantitative Trait Loci (QTL) conferring disease resistance in crop plants, very few have utilized QTL information in breeding programmes. The challenge for plant breeders is how to effectively integrate molecular marker-assisted selection (MAS) with phenotypic selection in the creation of new parental lines and cultivars. With the availability of userfriendly, high-throughput, automated marker technologies, coupled with powerful bioinformatic tools for data mining and novel breeding procedures like marker-assisted recurrent selection (MARS), MAS will become more attractive and affordable to many breeding programmes. This article presents the basic methodology of tagging genes/QTL for disease resistance, prerequisites of MAS for disease resistance (including gene pyramiding), and some successful examples of MAS applications in improving disease resistance in crop plants.

Global Maize Program

Text in English

INT3057