RESEARCHES CONCERNING IMPROVING METHODS OF IN VITRO MICROTUBERS PRODUCTION

Five genotypes of potato ( Solanum tuberosum L. ) were induced to form microtubers under two in vitro culture conditions (continuos darkness and light). Cultures maintained under continuos darkness (with a temperatue of 17 0 C) had a higher yield with a greater number of microtuber (1.394/plantlet) than those maintained under long days (16 h of light/day) combined with temperature of 20 0 C. In the last case the microtubers were higher, with with the highest average weight of 0.602 g. Three phytohormones it was used: coumarine, benzylaminopurine and salicylic acid. Regarding the average number of microtubers obtained when it was used coumarine and salicylic acid, the highest average number of microtubers was recorded (1,135 microtubers/plantlet).  The study had been performed also on two fractions of the of sugar quantity (80 and 140 g/l), but they had less influence compared to the varieties.