Priming with smoke-derived karrikinolide enhances germination and transplant quality of immature and mature pepper seed lots

The aim of this study was to test the effect of the smoke-derived compound, karrikinolide (KAR1), and hydropriming treatments on the seed germination of pepper (Capsicum annuum L.). The effect of priming treatments on seedling emergence percentages and rates, seedling fresh and dry mass, catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity of immature and mature seed lots for four pepper cultivars (Kandil D., Surmeli, Yaglık and Corbacı) harvested in 2015 and 2016 were evaluated. Priming with 10− 7 M KAR1 enhanced seed germination and seedling emergence for seeds from both harvest periods, and was more influential on immature seeds than mature seeds. Specifically, priming with KAR1 improved germination by more than 20% in immature seeds, compared to around 10% in the mature seeds. The differences in seedling emergence were 18% and 22% in 2015, and 21% and 22% in 2016, respectively. Priming with KAR1 increased catalase activity, but reduced APX and SOD activity in both seed lots for cultivar Corbacı. Thus, results indicate that priming with KAR1 can be used as an enhancing treatment in the cultivation of pepper seeds, and that the benefit is greater in immature seeds than in mature seeds, regardless of the cultivar or year of harvest.