Optimized breeding strategies for multiple trait integration: I. Minimizing linkage drag in single event...

Area of Science:

• Plant breeding
• Genetics
• Biotechnology

Background:

• Multiple Trait Integration (MTI) converts elite varieties for value-added traits using backcross breeding.
• Recovering original performance alongside new traits is key for MTI success.
• Single event introgression is the critical first step in MTI.

Purpose of the Study:

• To explore marker-aided backcross conversion feasibility for 15 transgenic events in maize.
• To minimize residual non-recurrent parent (NRP) germplasm, especially linked to the introgressed event.
• To identify optimal breeding strategies for efficient single event introgression.

Main Methods:

• Computer simulations were used to test various selection schemes (e.g., three-stage, modified two-stage).
• Breeding goals included <8 cM residual NRP germplasm genome-wide and ~1 cM near the event.
• Evaluated donor parent selection criteria based on introgression history and genetic similarity.

Main Results:

• A five-generation marker-aided backcrossing strategy achieved the breeding goal.
• Optimal strategies involved specific population sizes and selection intensities across generations (BC1-BC5).
• Conversion efficiency depended on donor parent genetic similarity, with higher similarity reducing required backcross generations.

Conclusions:

• Single event introgression for creating multi-event stacked hybrids is achievable.
• Developed strategies provide a pathway for producing high-quality starting materials for MTI.
• This research supports efficient development of elite maize hybrids with multiple value-added traits.