Germination biology of tropical soda apple (Solanum viarum)

Tropical Soda Apple (Solanum viarum Dunal) is an introduced invasive perennial weed that has been under eradication management in New South Wales (NSW) Australia since 2010. A series of laboratory and glasshouse studies were conducted to measure the effect of various factors on the germination of S. viarum seed. The viability of seed collected on the NSW Mid-North Coast was high (> 90%), and dormancy was low (< 10%). The seed is expected to persist in the local environment for more than 3 years. In local conditions, S. viarum germination has very few environmental limitations. Germination can occur when diurnal variation in temperature is > 5°C, minimum temperature > 10°C and maximum < 35°C. This species can survive and germinate with more than 20 mm per week of rainfall, soil with a range of pH (4–8), saline condition (< 100 ppm), and different burial depths (0–10 cm). S. viarum is well suited to becoming a significant weed of coastal Eastern Australia given the broad range of conditions in which its seed is capable of germinating. This information is important for the refinement of local S. viarum management plans.