Unravelling genomic and environmental contributions to nitrogen-use efficiency in tropical maize through Bayesian causal forests

In a tropical maize breeding panel of 614 single-cross hybrids, ideal nitrogen increases grain yield by +0.59 (95% credible interval 0.51 to 0.67) and raises plant and ear height.

• Why it matters: Breeding for nitrogen-use efficiency needs genotype- and environment-specific nitrogen response, but many genomic methods estimate associations rather than formally identified causal effects.
• What they did: A multivariate Bayesian causal forest estimated the causal effect of an ideal versus low nitrogen regime on grain yield, plant height, and ear height using a designed within-plot contrast and genomic moderators from leading principal components.
• The result: Effect heterogeneity was almost entirely environmental, with only a small genotypic component and negligible genotype-by-environment interaction, and the model supports transparent, uncertainty-aware nitrogen-response analysis.

AI summary of the abstract · may contain errors · not medical advice · read the paper.