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.

Variation of Residual Sexuality Rates along Reproductive Development in Apomictic Tetraploids of .

Most apomictic plants are facultative, maintaining the ability to reproduce sexually at different frequencies depending on the taxa, ploidy, and reproductive stage. In this context, species are good model systems for studies evaluating the varying levels of apomixis expression. We aimed to identify, in apomictic tetraploid species, the degree of apomixis and residual sexuality in three stages of reproductive development, and if their expression varies along them in order to predict their realized impact on the genetic diversity of future generations.

Chromosome studies in Orchidaceae from Argentina.

The center of diversity of Argentinean orchids is in the northeast region of the country. Chromosome numbers and karyotype features of 43 species belonging to 28 genera are presented here. Five chromosome records are the first ones at the genus level; these taxa are Aspidogyne kuckzinskii (2n = 42), Eurystyles actinosophila (2n = 56), Skeptrostachys paraguayensis (2n = 46), Stigmatosema polyaden (2n = 40) and Zygostates alleniana (2n = 54).