Effects of cultivar, culture medium, and plasma treatment on callus induction in Capsicum spp. through in vitro

Four chili pepper cultivars were successfully germinated on MS medium under in vitro conditions. PEP12 cultivar showed the highest germination speed and rate throughout all weeks, while ANT4 cultivar had a low germination rate in the 2nd week but an increased rate in the 3rd week. PEP6 cultivar had the lowest germination rate in the 3rd week, and YS cultivar had a moderate germination rate in all weeks. Callus derived from the hypocotyl of ANT4 on MS medium supplemented with 2 mg/L 2,4-D and 0.5 mg/L kinetin showed the highest callus induction efficiency (67.38 mm2). The callus induction experiment using air plasma jet treatments on PEP12 and YS revealed that PEP12 exposed to plasma for 9 seconds exhibited the highest callus growth rate at both the 2nd and 4th weeks. In contrast, YS consistently showed lower growth than PEP12 under all conditions. However, plasma treatments, even at the maximum exposure of 12, was not significantly differed as compared to the control group, indicating that plasma had only a minimal impact on callus growth, with most observed variations attributable to cultivar effects.