In vitro Growth of Alternaria alternata Isolated from Strawberry under Constant Light or Constant Darkness Conditions

The first step in scientific studies on Alternaria alternata is the development of the pathogen in vitro. For this purpose, in addition to many media, environmental factors such as light, temperature, and chemicals should be considered and evaluated. On the other hand, studies on these issues can help us reveal the pathogen's habitat and the ways to manage it. A correct optimization will ensure that subsequent studies are carried out healthily. In this study, the development of the phytopathogen, Alternaria alternata, isolated from strawberries, was investigated under constant light and constant darkness conditions. Colony diameter, colony development rate, conidiospore amount, and colony color were evaluated by observation and measurements. The results showed that on the 8th day, the colony diameter was 58 mm in light and 61,7 mm in the dark, and the colony development rate was 72.7% in the light and 77% in the dark. The numbers of conidiospores were about 2×107 conidiospores/mL in light and dark. Colony color was evaluated from both the front and back in terms of the Red/Green/Blue color ranges method (RGB), and no statistically significant difference was found in either color or any other measured parameter. The results showed that A. alternata isolated from strawberries used in this study can be grown in continuous light or continuous dark conditions without any developmental differences.