Chromosomal evolution and polyploidy dynamics in tribe Andropogoneae (Poaceae: Panicoideae): insights from phylogenomic reconstruction

Abstract

O_LIThe dissertation explored the chromosomal evolution of 230 species in the Andropogoneae tribe (Poaceae), which includes 1.224 species, using a detailed search of literature and databases. The phylogenetic analysis was based on complete plastome sequencing, and ancestral reconstruction utilized Bayesian inference and character optimization. C_LIO_LIResults indicated high diversity, with 46 variations in chromosome number (2n), ranging from 8 to 140, and 30% of species exhibiting polyploidy. This suggests multiple chromosomal alteration events occurred during the tribes evolution. C_LIO_LIThe chromosome number 2n = 20 was identified as the ancestral state for most internal nodes of the tree and confirmed as predominant in the Andropogoninae subtribe. However, more recently divergent taxa displayed higher chromosome numbers. C_LIO_LIThe research concludes that chromosomal variation is dynamic and complex. It emphasizes the importance of obtaining more chromosomal data to fill knowledge gaps and achieve a more complete understanding of the diversity and evolutionary mechanisms shaping the Andropogoneae tribe. C_LI