Effect of photoperiod and KNO3 concentration on the induction and development of potato (Solanum tuberosum) microtuber in vitro

Abstract. Choirunnisa JP, Wardana R. 2021. Effect of photoperiod and KNO3 concentration on the induction and development of potato (Solanum tuberosum) microtuber in vitro. Cell Biol Dev 5: 70-75. Potato (Solanum tuberosum L.) is a carbohydrate source plant that was developed as an alternative to food diversification. The availability of quality potato seeds is very limited due to the high attack rate of bacteria and viruses. The demand for potato seeds can be fulfilled by developing potato microtuber through the application of plant tissue culture. The purpose of this research was to determine the response of potato microtuber formation with different photoperiods and KNO3 concentrations. This study design uses a factorial Completely Randomized Design (CRD) with 5 replicates. The first factor is 3 levels of photoperiod (8 hours/day, 12 hours/day, 16 hours/day). The second factor is 3 levels of KNO3 (1900 mg/L, 2850 mg/L, 3800 mg/L). The study was conducted by observing the age of microtubers initiation, number of shoots, number of roots, number of microtubers, the diameter of microtubers, and wet weight of microtubers were analyzed using SPSS. The results showed that the combination treatment of 8 hours/day photoperiod and KNO3 concentration of 3800 mg/L could accelerate the initiation of microtubers at 8 DAP (Days After Planting). The concentration of 3800 mg/L KNO3 can increase the number of roots and microtubers, the diameter of microtubers, and the wet weight of microtubers. The highest diameter of microtubers (17.89 mm) and the highest wet weight of microtubers (278.81 mg) were found in the photoperiod of 16 hours/day. This study concludes that the higher concentration of KNO3 and the longer photoperiod could be used for the induction and development of potato microtubers, while the short photoperiod could be used to accelerate microtubers initiation