Determination of response of spinach varieties against downy mildew under ecological conditions of Sakarya province

Spinach downy mildew (Peronospora farinosa f.sp. spinaciae) is one of the most important diseases in spinach cultivation. In recent years, the development of varieties resistant to the races of Peronospora farinosa fsp spinaciae in breeding studies on spinach and the cultivation of these varieties in large areas has led to the formation of new races. While only 3 races of Peronospora farinosa f sp spinaciae were defined before the 1990s, today there are 17 different races. This study was conducted with 34 spinach varieties registered by the Ministry of Agriculture and Forestry, Seed Registration and Certification Center Directorate in our country in the 2018-2019 production seasons in order to determine the reactions of some spinach varieties sold in the market against mildew under the ecological conditions of Sakarya. In addition, the oospore contamination of the seeds used in the experiment was determined according to the washing test method. Evaluations were made considering the disease incidence and the disease severity. The trial was established in the village of Bayat in Sakarya province in 2018 according to the randomized blocks trial design. First exits in the experimental area started 15 days after the planting date and were completed in 21 days depending on the varieties. The first symptoms of Mildew disease were detected on 16.12.2018. In the experiment, the disease was evaluated twice in dates of 27.01.2019 and 10.02.2019. During the experiment, no disease was observed in Volans and Amador varieties. In other varieties, the severity of the disease varied between 0.17% and 41.50%, and the incidence rate varied between 1% and 72.75%. The seeds were examined according to the washing test protocol and contaminated seeds by oospores determined in 6 of 34 (17.65%) spinach varieties. The sporongiophore structure of the pathogen was determined in 2 varieties (5.88%). It was determined that the number of oospores varied between 120-1360.