Polyploidization contributes to the forms, heights, and species richness of plants

Whether plant life form influences the long-term survival of polyploid lineages remains an important unresolved question in plant evolution. Previous surveys have suggested that perennial herbaceous plants harbor higher proportions of neo-polyploids, but broad phylogenetic validation using genomic and ecological data has remained limited. The current explosion of plant genome sequences—heavily enriched with horticultural and agronomic species—offers an unprecedented opportunity to test this hypothesis across diverse paleopolyploid lineages, bridging evolutionary biology and crop science. Here, we analyzed 351 seed plant genomes, encompassing major cereals, vegetables, fruits, and their wild relatives, to investigate how recursive polyploidization interacts with plant form evolution. Phylogenetically informed comparative analyses revealed that lineages experiencing more paleopolyploidization events are significantly more likely to exhibit herbaceous growth forms and reduced plant stature. These patterns were especially pronounced in eudicots, which are enriched for herbaceous species with complex paleopolyploid histories. Furthermore, phylogenetic generalized least squares analyses suggested that herbaceous lineages, particularly short-statured crop species, exhibit elevated synonymous substitution rates relative to woody and vine plants. Plant stature also showed contrasting relationships with polyploidization across growth forms, with woody plants exhibiting negative associations whereas herbaceous plants displayed positive correlations. Together, these findings provide a phylogenetically informed framework for understanding how recursive genome duplication contributes to herbaceous growth strategies, accelerated molecular evolution, and plant diversification.