REPRODUCTIVE SYSTEM of Mimosa scabrella IN CONSECUTIVE REPRODUCTIVE EVENTS IN THE MOUNTAINOUS REGION OF SANTA CATARINA STATE

Abstract

The reproductive system determines evolutionary inheritance of populations by establishing patterns of gametes union to originate the next generation. The objective of this study was to investigate the mating system of Mimosa scabrella Benth. (bracatinga), a Brazilian tree species with socioeconomic and ecological importance, in a population of the mountainous region of Santa Catarina state, in two consecutive reproductive events. The analyzes in the 2015 and 2016 reproductive events were lead with isoenzymatic markers and the mating system characterization was performed based on mixed crosses and correlated crosses models, and the means of each parameter were statistically compared. Among the results, the multilocus outcrossing rates (tm(2015): 0.925 and tm(2016): 0.845) showed high magnitude and differed from the unit; the self-fertilization rates were significantly different from zero (s (2015): (0.075 and(2016): 0.155) indicating that the species does not show self-incompatibility. In addition, the positive outcrossing rates among relatives (tm-ts(2015): 0.142 and tm-ts(2016): 0.170) suggest inbreeding crosses in the population. The highest proportions in offspring were half-sibs (2015: 0.736 and 2016: 0.579), suggesting predominance of randomness at crossings. From this it is concluded that M. scabrella has a mixed mating system, with predominance of crossing at population level.

One Step Away From Extinction: A Population Genomic Analysis of A Narrow Endemic, Tropical Plant Species

“…As with M. catharinensis , high outcrossing rates have been reported for many Neotropical plant species (e.g., Ward et al, 2005 ; Feres et al, 2012 , 2021 ; Nazareno and Reis, 2012 ; Spoladore et al, 2017 ; Godoy et al, 2018 ; Montagna et al, 2018 ; Sujii et al, 2021 ), including two congener Mimosa species ( Moreira et al, 2011 ; Arruda et al, 2020 ). Studies on populations of M. scabrella ( Arruda et al, 2020 ), for instance, showed a similar reproductive pattern with high outcrossing rates ( t =0.925/0.845) and low estimates of selfing ( s =0.075/0.155). For M. catharinensis , the interpretation of negative F IS values coupled with high t values should be viewed with caution due to the distinct biology of the species (i.e., production of seedless pods and absence of seedlings in the study area).…”

“…Such a wide range in outcrossing rates for mixed-mating species are common and can change over time and space due to environmental conditions and intrinsic population features, such density and demographic structure (e.g., Wright et al, 2013). As with M. catharinensis, high outcrossing rates have been reported for many Neotropical plant species (e.g., Ward et al, 2005;Feres et al, 2012Feres et al, , 2021Nazareno and Reis, 2012;Spoladore et al, 2017;Godoy et al, 2018;Montagna et al, 2018;Sujii et al, 2021), including two congener Mimosa species (Moreira et al, 2011;Arruda et al, 2020). Studies on populations of M. scabrella (Arruda et al, 2020), for instance, showed a similar reproductive pattern with high outcrossing rates (t = 0.925/0.845) and low estimates of selfing (s = 0.075/0.155).…”