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. All populations of the four species were pure tetraploid and had a sexual and stable reproductive mode. However, some populations of and showed low levels of apospory. Populations of and had low seed sets under self-pollination but were fertile under open pollination, showing that self-incompatibility likely caused self-sterility. In contrast, populations of or showed no evidence of apospory, and seed sets in both self- and open pollination conditions were high, suggesting that they are self-compatible due to the absence of pollen-pistil molecular incompatibility mechanisms. The evolutionary origin of the four species could explain these differences. This study supplies valuable insights into the genetic systems of species, which could have implications for their conservation and management.