Determination of solanum ameri̇canum ecotype reactions against the gray leaf spot disease caused by stemphylium solani

The most widely grown tomato from Solanaceae family has an indispensable role in human nutrition in the world. However, there are fungal diseases that limit tomato production and destroy the photosynthetic ability of the plants, causing great economic losses. In recent years, due to global climate change, there has been a significant increase in infections caused by Stemphylium solani, which causes gray leaf spot disease in the Mediterranean and Aegean regions of Türkiye. Especially in Antalya which produces more than 60% of Turkey's winter tomato production, gray leaf spot disease has commenced to intensify due to the increase in humidity and temperature. A serious increase has been seen in gray leaf spot disease caused by fungal S. solani in plastic greenhouses where intensive winter tomato production is carried out, and the best method of control of the agent is the development of resistant varieties. However, Turkiye has neither genetic source of tomatoes nor resistant commercial varieties available on its market. Hence, genetically resistant varieties are needed to control the fungal disease. This study aims to test 25 ecotypes of Solanum americanum, a very close relative of tomato, with S. solani isolated from Antalya to reveal their phenotypic reactions and to determine genetically resistant S. americanum ecotypes against this fungal pathogen. The fungal disease agent was isolated from tomato plants grown in plastic greenhouses and identified morphologically and molecularly. In inoculations with the identified S. solani fungal isolate, the reactions of 25 ecotypes against the disease were determined as 6 of the tested ecotypes were found to be resistant, 3 of them are moderately resistant and 16 were found to be susceptible to this disease agent. Using the S. americanum plant, which has all known genetic characteristics, their genetic features to the pathogen have revealed for the first time as a model plant. The development of commercial tomato varieties has been paved by using the genes obtained from both genetically resistant and susceptible plants.