In vitro cultivation of callus cells from nodes and internodes of Capsicum annuum cv. All Big

Cell suspension cultures can be a valuable system for production of secondary metabolites. Capsicum annuum is a pepper species largely studied due to its biologically active compounds. The objective of this study was to establish a protocol for callus induction in nodes and internodes of C. annuum cv. All Big and to determine the callus growth curve, with focus on the deceleration phase, when the callus cells must be cultivated in a liquid medium in order to generate a cell suspension system. Nodal and internodal segments were submitted to media supplemented with the growth regulators 2,4-D and BA in factorial combination. After 49 days, the percentage of explants where callus induction occurred (%CI), the explant area covered by callus cells (ACCC), and the fresh weight of the explants were evaluated. In order to determine the growth curve, the explants were cultivated in the media supplemented with the growth regulators that resulted in the highest callus cell proliferation, weighing the calluses in the subsequent 49 days. The treatments that resulted in the highest %CI, ACCC and callus weight were 4.52 µM 2,4-D without BA for nodal explants and 9.05 µM 2,4-D + 2.22 µM BA for internodal explants. The growth curves of the calluses of the two types of explants followed a sigmoid pattern with six distinct phases; lag, exponential, linear, deceleration, stationary and decline. The deceleration phase started on the 27th and on the 19th day, respectively, for nodal and internodal explants.