The influence of exogenous capsaicin application on the germination, seedling growth, and yield of pepper

The aim of this research was to investigate the effect of capsaicin application in different doses (0.0, 0.1, 1.0, 10.0, 25.0, 50.0, 100.0, and 200.0 ppm) on the germination, seedling growth, and yield of pepper plants (Capsicum annuum L. `Burdem). For this purpose, capsaicin was applied at several stages: (i) to the pepper seed before sowing, (ii) to the leaves during the 3rd to 4th true leaf stage for seedling quality evaluation, and (iii) to the leaves before planting in a greenhouse. There were no statistical differences among capsaicin doses and the control with respect to germination and emergence, but the highest germination and emergence values and the shortest germination and emergence time were observed for seeds treated with 0.1 ppm of capsaicin (even after 6 months of storage). For 50.0 ppm, the germination and emergence percentage decreased and the time significantly increased, while germination and emergence were not observed for 100.0 and 200.0 ppm. The seedlings treated with 1.0ppm of capsaicin had the highest shoot fresh weight, stem diameter, number of leaves, and leaf area. There was no statistical difference among treatments in terms of relative water content, chlorophyll a and b, ascorbate peroxidasc, and superoxide dismutasc. The number of fruits/plant (100 fruits/plant) and fruit yield (0.89 kg/plant) in plants treated with 50.0 ppm of capsaicin were higher than in other treatments and the control. The results indicated that capsaicin has the potential for improving germination, seedling quality, and pepper yield.