Optimized breeding strategies to harness genetic resources with different performance levels

Area of Science:

• Plant breeding
• Genetics
• Agricultural science

Background:

• Limited genetic diversity in elite germplasm hinders long-term genetic gain and increases vulnerability to stresses.
• Efficient strategies are needed to broaden the genetic base of commercial breeding programs without sacrificing short-term variety release.

Purpose of the Study:

• To propose and evaluate a strategy using genomic selection and optimal cross selection for recurrently improving genetic resources.
• To bridge improved genetic resources with elite lines and manage introductions into elite breeding populations.
• To ensure consistency in the genetic base broadening strategy by jointly identifying bridging, introduction, and elite crosses.

Main Methods:

• Simulated breeding programs were used to compare the introduction of donors with varying performance levels, directly or indirectly after a bridging step.
• The effect of training set composition on introduction success was evaluated.
• Optimal cross selection was employed to balance genetic value and diversity.

Main Results:

• Recurrent introduction of improved donors can maintain genetic diversity and enhance mid- to long-term performance with minimal short-term penalty.
• A bridging step significantly increased mid- and long-term genetic gain when introducing lower-performing donors.
• Marker effects estimated from broad training populations (donor x elite and elite x elite progeny) are recommended for identifying crosses.

Conclusions:

• Guidelines are provided for leveraging polygenic variation from genetic resources to broaden elite germplasm.
• The proposed strategy balances genetic gain and diversity for sustainable crop improvement.