OPTIMICATION OF SCHEMES FOR REPRODUCTION OF STEVIA VARIETY 'STELA'

In Agricultural Institute -Shumen it has been carried out maintenance and multiplication of the first Bulgarian stevia variety `Stela', certified in 2017. In vitro technics for maintenance and micropropagation are used, as well as in vivo development of seedlings from cuttings by preservation and reproduction of rhizomes. During the last years are often the conditions of warm and continuous autumn with a regime of the short day from the end of September, which favors the reproductive development of seeds. The results for the measured indices of height, number of stems, fresh and dry mass and the calculated randeman and dry leaves yield of seed off-springs are indicative for the stabilization of comparatively high levels of productivity of elite clones of the variety `Stela'. The assessment shows that the most effective scheme for practical realization of seedlings is by sowing seeds in controlled conditions in January-February, diving off the germinated and stabilized plants in April-May, transplanting in June-July and receipt of formed rhizomes in September-October, which, after preservation to be realized during the next period.