Alternative Evolutionary Pathways in Involving Allotetraploidy, Sexuality, and Varied Mating Systems.

The genetic systems of species have not been extensively studied. We analyzed the ploidy, reproductive mode, mating system, and fertility of four species-, , , and . An analysis of 378 individuals from 20 populations of northeastern Argentina was conducted.

Sexual modulation in a polyploid grass: a reproductive contest between environmentally inducible sexual and genetically dominant apomictic pathways.

In systems alternating between sexual and asexual reproduction, sex increases under unfavorable environmental conditions. In plants producing sexual and asexual (apomictic) seeds, studies on the influence of environmental factors on sex are equivocal. We used Paspalum intermedium to study environmental effects on the expression of sexual and apomictic developments, and on resulting reproductive fitness variables.

Intraspecific ecological niche divergence and reproductive shifts foster cytotype displacement and provide ecological opportunity to polyploids.

Background And Aims: Niche divergence between polyploids and their lower ploidy progenitors is one of the primary mechanisms fostering polyploid establishment and adaptive divergence. However, within-species chromosomal and reproductive variability have usually been neglected in community ecology and biodiversity analyses even though they have been recognized to play a role in the adaptive diversification of lineages.

Methods: We used Paspalum intermedium, a grass species with diverging genetic systems (diploidy vs.