Quantitative Insights into the Genetic Mechanisms of Crop Heterosis

Heterosis, the universal phenomenon in which F₁ hybrids exhibit superior performance compared to their parental lines, is widely exploited in modern agriculture for improving crop yield, yet its genetic mechanisms remain incompletely understood. The contributions of parental genomic sequence variants to heterosis have been extensively investigated. Recent advances in transcriptomics, proteomics, and metabolomics offer new quantitative perspectives on the molecular basis of crop heterosis. This review summarizes current evidence on inheritance patterns: additive, partially dominant, dominant, and overdominant effects. We highlight that the contributions of these effects to heterosis vary by genotypes, traits, tissues, populations, developmental stages, omics datasets, growth environments, and species. The additive effect, which can be utilized to predict heterosis for F₁ hybrids and accelerate the breeding of hybrid crops, has been identified as a predominant inheritance pattern in complete diallel crosses. We propose that integrating multi-omics data and quantitative analysis of inheritance patterns can deepen our understanding of its genetic mechanisms and accelerate the breeding of elite hybrid varieties. This approach provides a framework for predicting breeding and the rational design of high-yield crops.