Seed-dormancy variation in natural populations of two tropical leguminous tree species: Senna multijuga (Caesalpinoideae) and Plathymenia reticulata (Mimosoideae)

Abstract

Senna multijuga and Plathymenia reticulata are tropical tree species native to the Brazilian Atlantic Forest and the Brazilian Cerrado, respectively. Seed-coat dormancy variation was evaluated within and among natural populations of these two species. Scarified and non-scarified seeds from different plants within populations were germinated at 28°C, and the percentage of germinated seeds was estimated for both species. Mean germination percentages of non-scarified seeds tended to be higher for P. reticulata populations (40 and 62%) than for S. multijuga populations (9 and 35%). After scarification, germination percentages increased significantly in both species, with all populations showing mean values above 84%. The level of seed dormancy, evaluated through the experiment with non-scarified seeds, differed significantly within and among populations of both species (P < 0.05). The values of the coefficient of genotypic determination were high for populations of both species (b = 0.85). Although this coefficient is an overestimation, since it includes non-genetic maternal effects, its high values suggest that a considerable part of the phenotypic variation in seed dormancy in S. multijuga and P. reticulata is of genetic origin. Variation in seed dormancy can be an important factor for increasing genetic diversity in populations of these species, making them able to respond to environmental changes.

Sensitivity cycling in physically dormant seeds of the Neotropical tree Senna multijuga (Fabaceae)

“…Lacerda et al . () reported that maternal effects were responsible for variation in seed dormancy between two populations of S. multijuga . Furthermore, we showed that seed size plays a role in control of PY‐break, wherein seeds have different degrees of sensitivity in relation to their size.…”

Variability in Fruit and Seed Morphology Among and Within Populations of Plathymenia (Leguminosae - Mimosoideae) in Areas of the Cerrado, the Atlantic Forest, and Transitional Sites

“…Variability in seed size may also be seen as a consequence of random processes, such as genetic drift. In fact genetic diversity among and within populations of P. reticulata has been reported (Lacerda et al, 2001(Lacerda et al, , 2002(Lacerda et al, , 2004. Moreover, habitat differences among and within populations may be promoting phenotypic differences in seed sizes.…”

“…This variation could be due not only to different selection pressures, but also to genetic drift or environment variability. As genetic differences have been shown among and within populations of P. reticulata (Lacerda et al, 2001(Lacerda et al, , 2002(Lacerda et al, , 2004 and environmental differences are present among the studied habitats (Goulart et al, 2005), we predicted that these differences would lead to morphological diversity in fruits and seeds.…”

Diversity of Naturalized Hairy Vetch (Vicia villosa Roth) Populations in Central Argentina as a Source of Potential Adaptive Traits for Breeding

“…EU cultivars had lower PY values compared to AR cultivars and naturalized accessions. PY is a highly heritable trait (Hudson et al, 2015) thus it could be useful germplasm for both breeding and artificial (or natural) selection for higher or lower levels of dormancy (Lacerda et al, 2007). It is probable that observed differences between accessions could be explained by genetic adaptations of HV to the local environment (Baskin and Baskin, 2014) as shown in pea (Hradilová et al, 2019) or by selection for improved genotypes (Fuller and Allaby, 2009;Kluyver et al, 2013;Renzi et al, 2016).…”