Investigation of the identification, germination biology, and management strategies of solanum species occurring as weeds in agricultural areas of the southeastern anatolia region

This study aimed to identify Solanum species collected from different locations in the Southeastern Anatolia Region using morphological and molecular methods; to investigate their germination biology, including dormancy-breaking treatments, germination at different temperatures, seedling emergence from different burial depths, and germinability in relation to the duration of soil burial; and to determine their herbicide dose–response relationships and economic thresholds in pepper. Morphological and molecular analyses identified two species: Solanum nigrum L. and Solanum villosum Mill. Among the dormancy-breaking treatments, GA₃ application was the most effective, resulting in 100% germination in both species at concentrations of 500 ppm and above. In the germination temperature experiment, the minimum, optimum, and maximum temperatures for S. nigrum were determined as 5 °C, 15–35 °C, and 40 °C, respectively, whereas the corresponding temperatures for S. villosum were 10 °C, 15–35 °C, and 40 °C. In the emergence-depth experiment, the highest emergence rates, reaching 100% in both species, were recorded at soil depths of 2 and 5 cm. In the study assessing germinability following different periods of soil burial, S. nigrum seeds retained high germinability after up to 24 months of soil burial when germination was tested using distilled water, whereas the germination of S. villosum varied depending on burial duration and depth. In the herbicide dose–response experiments, Mesotrione + Nicosulfuron was the most effective treatment for both species, whereas the responses to Bentazone + Imazamox and glyphosate varied between species. Economic thresholds differed between the two species, and S. nigrum was found to cause economically significant yield losses even at very low densities. The elucidation of the germination biology of S. nigrum and S. villosum is of critical importance for determining the appropriate timing of weed management practices. The herbicide dose–response results demonstrated interspecific differences, while the economic threshold experiment conducted under field conditions also revealed species-specific variation. These findings highlight the critical importance of accurate species-level identification and species-specific management strategies for reducing yield losses and improving decision-making processes in agricultural weed management.