Effect of Photoperiod and Nutritional-Shock on Increasing the Number of Minitubers from Apical Rooted Cuttings Grown in Coco-Peat

Currently, a variety of techniques for producing potato minituber have been investigated, including soilless aeroponic, hydroponic and deep-water culture systems. However, minitubers potato production in the greenhouse from apical rooted cutting grown coco-peat under a photoperiod and nutritional - shock system is a new and creative idea. Therefore, the objective of the study was to optimize the effect of photoperiod and nutritional-shock on growth performance and yield of first generation potato tuber production of potato plants. Potato variety ‘Atlantic’ was treated under 5 photoperiod – (8 h/day, 9 h/day, 10 h/day, 11 h/day and natural light) under nutritional-shock process with reducing N concentration in nutrient solution (0;25%; 50%;75% and 100%), the growth stage of plant to conduct nutritional-shock (30, 35, 40, 45 and 50 DAT), the implementation time of nutritional-shock (12, 24, 48 and 60 hours) and the combination of photoperiod (9 h/day, 10 h/day) and nutritional-shock (75%, 100%) on the formation and development of minitubers. The study revealed that photoperiod at 10h/day showed the best result with 7.4 tubers/ plant and 569.7 tubers m-2. The number of tuber stolons, average number of tubers and tuber yield was directly proportional to the decreasing in N concentration in the nutrient solution, in which the highest was the 100% reduction in N concentration with 9.3 tubers/plant, higher than the control treatment 300%. The nutrient shock treatment at 30 DAT in 48 ours gave the best tuber production efficiency. There was a strong interaction between photoperiod and nutritional-shock on the formation and yield of potatoes (10.6 tubers/plant, 308 tubers m-2).