Characteristics and methods to release seed dormancy of two ground cherry (Physalis) species

Abstract

Several ground cherry (Physalis) species have attracted significant interest due to their potential use in medicines. Nonetheless, these species are invasive weeds in some regions of the world, while cultivated for food and medicinal uses in the others. Physalis angulata is cultivated for its medicinal potential, whereas P. philadelphica is grown as a horticultural crop. Both species are regarded as invasive weeds in Turkey causing significant economic losses. These species are underutilized in the country and could serve as a valuable resource for agriculture and medicine industries. Therefore, we investigated the seed dormancy type, levels and methods of dormancy release for P. angulata and P. philadelphica. Seeds of different populations of both species (3 population per species) were collected from various elevation gradients in southeastern Anatolia region, Turkey. Numerous seed dormancy-release techniques were evaluated to understand the requirements for dormancy release. Significant differences were observed in seed dormancy level among species and their populations, while viability remained similar. Seeds P. angulata had higher dormancy level (73.07–98.78 % dormancy) than P. philadelphica (7.56–33.15 % dormancy). The level of seed dormancy was increased with increasing elevation gradient in both species. There were some germination inhibiting substances, which retarded seed germination of both species. This indicated that the dormancy type in both species belongs to physiological dormancy (PD). Running tap water proved the most effective treatment in releasing seed dormancy of all tested populations. Some of the dormancy breaking techniques, especially scarification with H2SO4, even suppressed germination. The knowledge of seed dormancy could be utilized to commercialize/cultivate both species in Turkey. Nevertheless, the result could also be used for the development of management strategies against the species where these are considered as invasive weeds.