Effects of ethyl methane sulfonate applicated at different doses on plant development, some physiological parameters and phytophthora capsici in pepper (capsicum annuum L.)

In this study, Kandil, Üçburun pepper varieties, and a local genotype known as Çermik pepper were mutated. This was done by using Ethyl Methane Sulfonate (EMS). The aim was to determine the resistance to root collar blight (Phytophthora capsisi) disease in pepper. This was done by obtaining productive, high quality, promising lines. To this end, the pepper seeds were exposed to the chemical mutagen EMS at doses of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.75%, and 1.0%. The study covered the M1 and M2 periods (2023–2024). In the M1 generation period, germination studies were carried out on the seeds. Studies were also carried out to determine the effective mutation dose in the seedling period, as well as the planting of seedlings in the field. In the M2 generation period, pepper seeds were planted using the mass selection method from the previous year. The seedlings in pots were infected with root rot disease in a greenhouse environment, and the necrosis length (cm) was measured. The planting of seedlings in the field took place, and at the end of the season, seeds were collected from the lines that had been selected using the single selection method. Morphological characterizations of the M1 and M2 generations were performed according to the identification criteria of the International Union for the Protection of New Varieties of Plants (UPOV) and the Central Directorate of Seed Registration and Certification (TTSM). When the harvest parameter was examined in the M2 generation, for which selections were made in mutation breeding studies, the highest total yield was found in the 0.3+9 hour treatment. The lowest yield was found in all other treatments in the lines belonging to the Üçburun pepper variety. In lines belonging to the Çermik genotype, the highest yield was determined by the 0.4% + 6-hour application, and the lowest yield was determined by the 1.0% + 6-hour and 1.0% + 9-hour applications. In lines belonging to the Kandil pepper variety, the highest yield was determined in the 0.2% + 9 hours treatment (20,253.10 g), and the lowest yield was determined in the 0.3% + 9 hours (6,816.90 g) and 0.75% + 9 hours (8,399.40 g) treatments. According to the obtained data, the use of chemical mutagens at increasing doses and for increasing periods of time decreased the germination rates of plant seeds and shortened plant height. The amount of proline in the leaves and the amount of enzymes such as SOD and CAT increased with increasing doses. According to the statistical results of all parameters obtained at the end of the study, the most productive lines from the three pepper varieties/genotypes were identified. The most productive lines of the Üçburun variety were obtained from the 0.3+9 hours, 0.2+9 hours, and 0.4+6 hours treatments. The most productive lines of the Çermik genotype were obtained from the 0.4+6 hours, 0.1+9 hours, and 0.2+9 hours treatments. The most productive lines of the Kandil variety were obtained from the 0.2+6 hours and 0.1+9 hours treatments. As a result, it seems possible to obtain variations in peppers through the use of chemical mutagens to develop new plant varieties. When the results are evaluated, it is thought that new lines are obtained by selecting varieties with high market value that are attractive and disease-resistant.