Molecular markers: actual and potential contributions to wheat genome characterization and breeding

Abstract

The demands for increasing global crop production have prompted the development of new approaches relying on molecular marker technologies to investigate and improve the plant genome. The merits of molecular markers make them valuable tools in a range of research areas. This review describes novel approaches based on modern molecular marker technologies for characterization and utilization of genetic variation for wheat improvement. Large-scale genome characterization by DNA-Wngerprinting has revealed no declining trends in the molecular genetic diversity in wheat as a consequence of modern intensive breeding thus opposing the genetic 'erosion' hypothesis. A great number of important major genes and quantitative trait loci have been mapped with molecular markers. Marker-assisted selection based on a tight linkage between a marker allele and a gene(s) governing a qualitative or quantitative trait is gaining considerable importance as it facilitates and accelerates cultivar improvement through precise transfer of chromosome regions carrying the gene of interest. The implementations of molecular markers in wheat genotyping, mapping and breeding complemented by speciWc approaches associated with the complex polyploid nature of common wheat are analyzed and presented.

Determination of leaf rust resistance genes Lr10, Lr26 and Lr37 by molecular markers in wheat cultivars registered in the Czech Republic

“…Many molecular markers have been described for Lr genes and often more markers based on different procedures have been developed for the same gene (http://maswheat.ucdavis.edu, Landjeva et al 2007). In the Czech Republic Ovesná (RICP, Prague) participated in the ring test for validation of several STS markers for Lr genes.…”

Genetic diversity in the U.S. hard red winter wheat cultivars as revealed by microsatellite markers

“…After 2000, a decrease in allelic richness was due to the qualitative changes in allelic composition. Replacement with alleles favourable for adaptation is a key feature for today's breeding approach, which has led to the apparent loss of allelic richness (Landjeva et al 2007), but the maintenance of gene diversity and high PIC values in the 2000s releases indicate positive changes in the most recent cultivars. Genetic diversity may not be well assessed using a particular decade because the pattern of changes may not happen in a defined number of years.…”

Genetic associations in the detection of QTLs for wheat spike-related traits

“…A tendency in the breeding process is introducing novel techniques and approaches that could improve current conventional breeding programs. Particularly, the advancement in the field of molecular biology by applying genetic marker technologies and new statistical approaches are powerful tools for indirect selection of valuable traits through marker-assisted selection (Landjeva et al, 2007). The detection of specific and precisely tagged chromosome regions responsible for the expression of certain agronomic traits could be an excellent contribution for the selection and generation of new high-yielding wheat varieties.…”