SNP reports of Cylindropuntia species from Dartseq used for population genetics analysis

Dioecy, the separation of sexes, is found in 6% of flowering plants. One
widely known hypothesis suggests that it is an adaptation to mitigate
inbreeding. A contrary hypothesis suggests that dioecy is an evolutionary
dead-end. However, contrasting patterns emerged from population genetic
studies that compared the genetic diversity between dioecy vs
hermaphroditic species. Specifically, in Silene it was shown that
dioecious species possess higher genetic diversity than hermaphroditic
species, challenging the dead-end hypothesis. To evaluate whether dioecy
is indeed advantageous, further studies are needed in systems with diverse
sexual systems such as the genus Cylindropuntia (Cactaceae). It
encompasses species with sexual separation observed solely in polyploids.
Notably, these polyploids (C. wolfii and C. chuckwallensis) share similar
ploidy, flower colors, and geographic proximity raising speculation about
their shared ancestry. Moreover C. wolfii has been reported to have a low
seed production highlighting the need to assess the reproductive
strategies of the species. Our first goal was to compare the genetic
diversity patterns among species with different sexual systems within the
genus Cylindropuntia (Cactaceae). Our second goal was to investigate
genetic shared ancestry among the polyploid species. As C. wolfii is
struggling to sexually reproduce our third objective was to investigate
whether it is dominated by clonal reproduction diversity parameters and
population structure. The clonality of C. wolfii was assessed using a
combination of field survey and genetic analysis. The pattern of genetic
diversity in species with diverse sexual systems did not support the
dead-end hypothesis. The field survey of C. wolfii revealed no seed
recruitment but the genetic analysis on the current adult plants showed
low signs of clonality suggesting that this species has recently shifted
to clonal reproduction. Results showed that overall, this genus had low
genetic diversity and high differentiation implying that it is vulnerable
to environmental threats.