Comparative analysis of molecular and morphological diversity in two diploid Paspalum species (Poaceae) with contrasting mating systems

REUTEMANN A.VERENA; ANA I. HONFI; KARUNARATHNE, PIYAL; ECKERS, FABIANA; HOJSGAARD, DIEGO; MARTINEZ ERIC J.

SEXUAL PLANT REPRODUCTION

SPRINGER

Lugar: Berlin; Año: 2023

0934-0882

Key Message Interspeciic comparison of two Paspalum species has demonstrated that mating systems (seling and outcrossing) contribute to variation (genetically and morphologically) within species through similar but mutually exclusive processes. Abstract Mating systems play a key role in the genetic dynamics of populations. Studies show that populations of seling plants have less genetic diversity than outcrossing plants. Yet, many such studies have ignored morphological diversity. Here, we compared the morphological and molecular diversity patterns in populations of two phylogenetically-related sexual diploids that difer in their mating system: self-sterile Paspalum indecorum and self-fertile P. pumilum. We assessed the morphological variation using 16 morpho-phenological characters and the molecular diversity using three combinations of AFLPs. We compared the morphological and molecular diversity within and among populations in each mating system. Contrary to expectations, selfers showed higher morphological variation within Populations, mainly in vegetative and phenological traits, compared to outcrossers. The high morphological variation within populations of selfers led to a low diferentiation among populations.At molecular level, seling populations showed lower levels of genotypic and genetic diversitythan outcrossing populations. As expected, selfers showed higher population structure thanoutcrossers (PhiST= 0.301 and PhiST = 0.108, respectively). Increased homozygous combinations for the same trait/locus enhance morphological variation and reduce molecular variation within populations in seling P. pumilum. Thus, seling outcomes are opposite when comparingmorphological and molecular variation in P. pumilum. Meanwhile, pollen low in obligate outcrossing populations of P. indecorum increases within-population molecular variation, but tends tohomogenize phenotypes within-population. Pollen low in obligate outcrossers tends to mergegeographically closer populations; but isolation by distance can lead to a weak diferentiation among distant populations of P. indecorum.