The purpose. To determine optimum regime for formation of tubers of grades of potato in vitro of different groups of ripeness depending on storey of cuttings of test glass plants and content of nutrient medium. Methods. Complex use of laboratory, mathematical-and-statistical, calculation-andcomparative methods and systems analysis. Results. Experimental data about influence of storey of cuttings of test glass plants and content of nutrient medium on induction of formation of tubers are resulted at reproduction of different by group of ripeness grades of potato in crop in vitro. Conclusions. The best productivity indexes are gained at growing microtubers of middle-ripening grade of potato Yavir on nutrient medium of Institute of irrigation farming agriculture of NAAS at plants from 1-3-rd storey of a cutting. So, the mass of average microtuber has made 502 mg, mass of microtubers for 1 plant -509,8 mg. Yield of microtubers in mass more than 350 mg -84,7%, intensity of formation of tubers made 101,5%.Key words: potato, grade, crop in vitro, storey of a cutting, microtuber, productivity.https://doi.org/10.31073/agrovisnyk201805-07Introduction. The main problem of potato growing in the south of Ukraine is the increased threat of the defeat of plants by viral, fungal and bacterial diseases, greatly complicates the management of seed production, reduces the quantity and quality of the crop [1-4], so the modern seed production of potatoes in this region, referred to as the zone of risky farming, is impossible without the improvement of existing methods of reproducing the healthy initial seed material in in vitro conditions. Analysis of recent research and publications. The effectiveness of the biotechnological method depends on a number of factors: the intensity of the illumination, the temperature regime, the duration of the photoperiod, and others [5][6][7][8][9].The basis of plant tissue cell culturing in in vitro condition is the composition of the nutrient medium, which includes micro-and macro salts, vitamins, stimulants, etc. [6, 8, 9-13]. Studies [14] show that even the plants parts which are spliting during the cutting are distinguished by the influence on the induction of microtuber formation and on the resistance of the plants against the viral infection [15]. It should be noted that various cultivars have their reaction to the same conditions of cultivation in in vitro conditions [16][17][18][19][20]. In addition, the complex influence of the differend tiers of steems, potato cultivars of different ripening groups and the composition of the nutrient medium is not well-studied, which means that their complex research acquires an urgency in solving the problem of optimizing the process of tuber formation in in vitro culture.The purpose of research. To determine the most optimal regimes of tuber formation of potato cultivars of different ripening groups depending of the parts of plants in vitro and the composition of the nutrient medium.Materials and methods of research. The studies were carried out under micr...
