Effect of paclobutrazol doses on seedling growth and quality in different pepper types

Paclobutrazol is the most important plant growth regulator used to control seedling height. The most important problem in paclobutrazol applications is the application method and dosage. Pepper is a species which has many genotypes, and the germination, emergence and seedling development strengths of these genotypes are often different from each other. This study aimed to determine the most effective doses of paclobutrazol in seedling cultivation of different pepper types. For this purpose, 8 pepper genotypes, including 1 hybrid and 1 standard variety or local population, were used in 4 different pepper types (bell pepper, green pepper, capia pepper and three-lobed pepper). In the study, 10, 20, 30, 40, 50 and 60 ppm paclobutrazol doses were applied to plants at two different seedling development stages. The first application was made when the cotyledon leaves reached a level where they were parallel to the ground. The second application was made when the first true leaves reached a width of 0.5 cm. In each application, 0.3 ml of paclobutrazol was sprayed onto the seedlings as a foliar spray, and 5 minutes after the application, irrigation was done to ensure that the paclobutrazol was washed from the leaves and reached the root area. Observations were made on seedlings 50 days after seed sowing. The experiment was conducted in three replications according to the split-plot design, where the main plots are genotypes and the sub-plots are paclobutrazol doses. In the study, as the paclobutrazol dose increased, a significant shortening in seedling height was observed. When seedling height and other quality parameters were evaluated together, 20 and 40 ppm PBZ doses were determined as the most effective doses, although they varied depending on the genotypes. Paclobutrazol doses of 20 ppm in Anemone Fı genotype, 30 ppm in Kandil, Gama Fı, Burdem and Esen Fı genotypes, and 40 ppm in Postal, Arima Fı and Tokat pepper genotypes were determined as the most effective doses. Paclobutrazol doses of 10, 50 and 60 ppm caused significant losses in seedling quality. As a result, it has been understood that paclobutrazol doses in pepper seedling cultivation should be determined according to the genotype to be grown, and a standard dose is not suitable for all genotypes.