Chengdao Li

The technologies of Marker-assisted selection (MAS), Doubled Haploid (DH), and Single Seed Descent (SSD) are now providing the basis for significant advances in the way wheat and barley breeding is carried out. In the barley breeding program in WA, for example, DH lines represent over 25% of the overall breeding program and 45% of the stage 2 or pure breeding component with the proportion of DH lines set to increase in the future. Since 1993, over 25,000 barley DH lines have been produced in WA. In addition 4,000 lines each year are produced from the SSD program. Doubled haploids and single seed descent reduce the time taken to release a variety by 2 to 3 years. However, large numbers of DH lines and SSD lines tested in the field and derived from the F1 of single crosses have limited genetic value. Marker assisted selection applied to segregating populations backcrossed, top-crossed or F2, both pre- and post DH production, and pre-single seed descent will enhance the genetic value of populations through the selection for desirable traits. In this view of the wheat and barley breeding programs, it is evident that major gaps exist in the suite of marker-trait combinations, as well as low cost/high throughput technologies for background selection (eg DArTs), that are available for application in the breeding program. Investigation of the DArT-type analysis in collaboration with the CAMBIA group indicated that the technology may have a role to play in the analysis of barley breeding lines. The status of new marker-trait combinations that are available for implementing the strategies discussed will be presented.