Linking quantitative genetics with community-level performance: Are there operational models for plant breeding?

Area of Science:

• Evolutionary ecology
• Plant breeding
• Agroecosystem science

Background:

• Plant breeding traditionally focuses on individual genotypes, posing challenges for predicting community-level biodiversity effects in agroecosystems.
• Developing effective intercropping practices requires new tools to predict outcomes at higher biodiversity levels, from crop covers to entire agroecosystems.
• Understanding interspecific indirect genetic effects (IIGEs) is crucial for designing breeding strategies that benefit crop communities.

Purpose of the Study:

• To review theoretical advances in evolutionary ecology for predicting artificial selection effects on community-level plant performances.
• To identify and evaluate operational approaches for modeling IIGEs in plant communities.
• To provide a framework for breeders and scientists interested in the genetic improvement and functioning of crop communities.

Main Methods:

• Literature review of theoretical advances in evolutionary ecology.
• Identification and categorization of three main approaches for modeling IIGEs at the community level: community heritability, joint phenotype, and community-trait genetic gradient.
• Discussion of the operational capacities, assumptions, and limitations of each approach.

Main Results:

• Three distinct approaches to modeling IIGEs were identified: community heritability, joint phenotype, and community-trait genetic gradient.
• Each approach is a specific case of a general multitrait, multispecies selection index, with choices depending on breeding targets and strategies.
• Quantitative, community-level genetic predictions are constrained by experimental complexity; qualitative predictions are recommended for comparing breeding strategies.

Conclusions:

• Existing approaches offer a theoretical framework for predicting community-level breeding outcomes, but practical application faces challenges.
• Estimating genetic covariances within and among species for IIGEs presents a significant obstacle.
• Future research should focus on overcoming these limitations to enable effective genetic improvement of crop communities and understand plant community functioning.