Seed germination dynamics of silverleaf nightshade (Solanum elaeagnifolium Cav.) and implications for effective weed management

Silverleaf nightshade (Solanum elaeagnifolium Cav.) is a noxious weed that threatens agricultural productivity and biodiversity worldwide. The long-term management of soil seedbanks along with the aboveground populations of silverleaf nightshade has the potential to effectively control the species in its introduced range. Implementation of this strategy requires insights into the germination behavior of the weed in response to various environmental stimuli and endogenous cues. We assessed the morphology and germination of silverleaf nightshade seeds from an agricultural farm, native rangelands, and an urban site in Texas, USA. The effects of growth substrate, phytohormones, and salt treatments on seed germination were also evaluated to identify potential stimulus that can be used to manipulate germination in the species. Results of the study showed that silverleaf nightshade seeds from the agricultural farm were the largest, while those from the Littlefield rangeland were the smallest. Seeds collected from the urban site and agricultural farm have higher germination rates than those sampled from the rangelands. Compared to domesticated crops, silverleaf nightshade seeds require longer imbibition time. Seed germination was better in potting mix than in sand or combined potting mix and sand and was significantly reduced by salt and abscisic acid treatments. Overall, results of the study highlight the crucial role of local environments in conditioning the transgenerational adaptation of species, particularly with respect to germination. Recommendations for silverleaf nightshade control are presented based on the observed variations in the germination behavior of populations within specific ranges.