The Role of Reproductive Modes in Shaping Genetic Diversity in Polyploids: A Comparative Study of Selfing, Outcrossing, and Apomictic Paspalum Species

REUTEMANN, A. VERENA; SCHEDLER, MARA; HOJSGAARD, DIEGO H.; BRUGNOLI, ELSA A.; ZILLI, ALEX L.; ACUÑA, CARLOS A.; HONFI, ANA I.; MARTÍNEZ, ERIC J.

Plants

MDPI

Año: 2025 vol. 14

Exploring the genetic diversity and reproductive strategies of Paspalum species isessential for advancing forage grass improvement. We compared morpho-phenological,molecular, and genotypic variation in five tetraploid Paspalum species with contrastingmating systems and reproductive modes. Contrary to previous findings, selfing(Paspalum regnellii and P. urvillei) and outcrossing (P. durifolium and P. ionanthum) speciesexhibited similar phenotypic diversity patterns, with low intrapopulation variability andno morphological differentiation among populations. The apomictic species (P. intermedium)exhibited low intrapopulation phenotypic variation but high population differentiation,indicative of genetic drift and local adaptation. Outcrossing species showed greater intrapopulationgenotypic variation than selfing species, which displayed a high populationstructure due to restricted pollen migration. The apomictic species exhibited the lowestintrapopulation molecular diversity, forming uniclonal populations with high interpopulationdifferentiation, highlighting the fixation of distinct gene pools via apomixis. Thisis the first report about genetic diversity in populations of sexual allopolyploid species ofPaspalum. Population structure in these allotetraploid Paspalum species is primarily shapedby how reproductive modes, mating systems, and geographic distribution influence geneflow via pollen and seeds. Our findings contribute significantly to the conservation andgenetic improvement of forage grasses, particularly for developing cultivars with enhancedadaptability and productivity.