Selection strategies for marker-assisted backcrossing with high-throughput marker systems.

Area of Science:

• Plant breeding and genetics
• Genomic selection and marker-assisted selection

Background:

• Marker-assisted backcrossing (MABC) is crucial for gene introgression but is hindered by high marker analysis costs.
• High-throughput (HT) assays offer cost reduction potential, necessitating new selection strategies for efficient breeding programs.

Purpose of the Study:

• To compare the properties of HT marker systems with single-marker (SM) assays.
• To develop optimal selection strategies for MABC utilizing HT assays.

Main Methods:

• Computer simulations using a genetic model with 10 chromosomes (160 cM each) to simulate dominant target gene introgression.
• Evaluation of a three-stage selection strategy combining SM and HT assays against HT-only genome-wide background selection.

Main Results:

• HT marker systems provide equally spaced markers, with high marker density (<10 cM) being of secondary importance for MABC.
• A three-stage selection strategy combining SM assays (for flanking markers) and HT markers (for background selection) is more efficient than HT-only selection.
• Combining SM and HT assays proved more efficient across various cost ratios, with increased population size in the first backcross generation further reducing costs.

Conclusions:

• Selection strategies integrating SM and HT assays enhance the efficiency and flexibility of MABC.
• Optimized population sizes in early backcross generations can significantly decrease overall program costs.