Diverse leaf functional and phenotypic traits in hybrid oak individuals: Unveiling genetic variation, adaptation, and evolutionary potential within Quercus Species.

Hybridization emerges as a formidable evolutionary force, countering differentiation and fostering adaptive variation within populations. Hybridization crafts novel plant traits suited for unique ecological niches, thus significantly contributing to evolutionary dynamics. Here, we collected 300 individuals from a mixed forest, home to four native oak species - Quercus acutissima and Q. variabilis (Cerris group), and Q. fabri and Q. serrata var. brevipetiolata (Quercus group). To evaluate hybridization's role in adaptability, these individuals were classified into six genetic categories: two purebred types, first and second-generation hybrids, and two backcross generations. The analysis covered 20 traits, encompassing both leaf functionality and phenotype, to unravel the nuances and adaptive strategies of hybrids in comparison to purebreds. Our findings revealed substantial divergence in leaf functional traits between the two species groups, with hybrids exhibiting higher leaf chemical elements and stoichiometric ratios, particularly in carbon, nitrogen, and phosphorus. Additionally, leaf area-related indices displayed significant distinctions between hybrid and purebred phenotypes. Notably, hybrids in the Cerris group demonstrated intermediate leaf fluctuation asymmetry, whereas those in the Quercus group exhibited higher levels than their purebred counterparts. Additionally, we revealed that hybrids exhibited higher leaf phenotypic plasticity compared to purebreds. Hybrid individuals, through hybridization and introgression processes, evolved their genetic makeup to enhance nutrient absorption and phenotypic plasticity, thereby increasing their resilience to environmental stress. This study provides critical insights into the role of hybridization in creating phenotypic variability and enhancing plant adaptability, crucial features for breeding, management, and conservation efforts in the face of global climate change. • Hybrid Oaks: Fix nitrogen, with unique leaf traits, showing vigor and adaptability. • Hybrid breeding with good traits contributes to forest management. • Introgression enhances hybrid growth and nitrogen-fixation, surpassing parental capabilities. [ABSTRACT FROM AUTHOR]