In recognising the need for a research program to establish molecular markers suitable for Australian wheat breeding, the Grains Research Development Corporation (GRDC) provided core funding to establish the National Wheat Molecular Marker Program (NWMMP) in 1996. The NWMMP established and analysed doubled haploid populations from 4 crosses, Cranbrook × Halberd, CD87 × Katepwa, Sunco × Tasman, and Egret × Sunstar.
The papers in this special issue document some of the outcomes from this national program and they fall into three broad categories:
The results on the molecular genetic mapping in the populations derived from three crosses (Cranbrook × Halberd, CD87 × Katepwa, and Sunco × Tasman) linking variation in traits to particular regions of chromosomes. These chromosomal regions define the locations of quantitative trait loci (QTLs). The establishment of the maps included the exploring of new marker technologies to complement the RFLP and the establishment of database for microsatellites. Potential candidate genes for a range of grain properties were derived from gene sequences expressed in developing endosperm and were assayed using single nucleotide polymorphisms in order to assign chromosomal locations.
The papers that follow these mapping related studies provide detailed analyses of a number of traits and provide the locations of the corresponding QTLs. Although many of the analyses used well-established programs such as MAP MANAGER, some of the analyses were also compared with single stage analyses that combined regression analyses of both the mapping and trait data.
The third broad group of manuscripts deals with the validation and implementation issues for markers associated with selected traits, e.g. a detailed examination of the application of markers for starch quality, flour color, and disease resistance genes in breeding programs and document the solving of specific problems that came up with application of DNA markers in breeding programs. A central aspect of marker application to breeding programs is the requirement of high throughput technologies and several papers in this special issue provide unique solutions, depending on the marker analysed, to the challenge of developing appropriate formats.
The papers in this special issue provide a glimpse of the impact many of the new biotechnological procedures will have on a major crop such as wheat. The databases underpinning the manuscripts set the stage for integrating new knowledge from model systems such as Arabidopsis where candidate genes for certain biological processes can be assessed for their significance in wheat. A key achievement of the NWMMP has been to provide the means for capturing new knowledge efficiently from model systems and move this forward in analysing the unique biological environment found in wheat.
The publication of this AJAR Special Issue represents a first-ever comprehensive and coordinated effort to publish the research outcome on wheat genome mapping in Australia.