Ilex paraguariensis A. St. Hil. (yerba mate) is a native species widely consumed in southern Brazil, a region that presents a current scenario of forest fragmentation. The objective was to evaluate the genetic diversity, genetic structure, and gene flow among cohorts of I. paraguariensis in two forest remnants. Genetic analyses were conducted using microsatellite markers from leaves from adult (Ad), regenerating (Reg), and seed-derived (Se) populations in Santa Catarina (SC) (ChapecÃ’s National Forest [CCO]) and Rio Grande do Sul (RS) (Teixeira Soares’ Municipal Natural Park [PTS]). We found unique alleles in both populations, eleven in the CCO and eight in the PTS. There was no significant difference in genetic diversity indexes, whereas high and significant fixation indexes were observed (FCCO = 0.394; FPTS = 0.319). The proportion of genetic variation obtained between populations was lower (8%) than the proportion within populations (92%). The presence of significant genetic structure was verified in the cohorts of I. paraguariensis for two study areas. Moreover, all pairwise genetic divergence between Ad and Reg, and Ad and Se cohorts was significant, except for Ad versus Reg in PTS. Aiming to maintain diversity over generations, we recommend the conservation of remnants and expansion of connectivity between fragments. Study Implications Ilex paraguariensis is a species of high consumption and of social, cultural, and economic importance in southern Brazil. It occurs naturally or was naturalized in highly fragmented forests, which may reduce genetic diversity. The genetic analyses of different cohorts of I. paraguariensis reveals the current status of the genetic diversity of the species and indicates how diversity is maintained over generations. Thus, the study provides information for its use and conservation, maintaining genetic diversity.

The success of Ilex paraguariensis cutting can be affected by the population of origin, as well as the genotype and the rooting environment. Therefore, the objective of this search was to test the vegetative propagation of I. paraguariensis cuttings from two populations and their genotypes inserted in two rooting environments. The populations tested were from Três Barras (TB) and Urupema (UR), both from Santa Catarina state, by selecting seven genotypes in each. After collecting and cutting, the populations and genotypes were evenly distributed in two rooting environments, one being a mini tunnel (MT) with irrigation by micro sprinklers and the other in a greenhouse with intermittent nebulization (GWIN) with temperature and humidity control. Survival was considerably low for both populations but with singular results, as TB was better adapted to GWIN (36.5%) and UR to MT (22.6%). The rooting of cuttings varied greatly in all perspectives. The TB population obtained the best rooting results inside GWIN (21.7%), while UR did not achieve 5% of rooting in MT (2.4%) nor in GWIN (3.2%). The genotypes TB6, TB3 and TB1 obtained the best rooting results for TB in GWIN (all above 30.0%), while only UR3 obtained significant results in GWIN (18.8%). These results, mainly regarding survival and rooting, confirm that there is a strong relation involving the origin place of the material, the individuals of a population and the rooting environments.