A.I. Morosov, G.P. Pushkina

There were studied five sorts of Mentha piperita on influence of natural growth regulators Cyrcon (a mixture of hydroxycynnamic acids) and Epin-extra (epy-brassinolid) on the crop of leaves and the essential oil yield during nonstabil meteorological condition of Nonblack sone of RF. There wese found out distinctions in bioregulators action at optimal and droughty wether. The studies have shown that during the droughty wetues the higher efficiency has exhibited Cyrcon. The increace of the leaves crop was 2.5-3.3 c/ga and the yield of essential oil was 11.0-17.2 kg /ga. The most important is that the latter during the dry season Cyrkon shows itself as the growth regulator as well as the antistress adaptogen, thus promoting an increase the stability of Mentha piperita to hydrothermal stress. Epin-extra action contrary to Cyrkon during the dry season were exhibited in lesser degree. The crop in crease on all sorts except Kubanskaya-6 was 1,2-2,4 c/ga. During the optimal wether conditions Epin-extra promoted an encrease of the leaves production on 2,6-4,5 c/ga and the essential oil yield on 6,4-14,2 c/ga. There should be mentioned that treatment of Mentha piperita with the growth regulators at the first year of vegetation promotes increasing the growth aggravation and development of cultures, increases the crop capacity, as well as diminishes the plants deth during the wither season. Thus, the correct selection of the growth regulators during the Mentha piperita cultivation at varions meteorological conditions has allowed to get stabil crops production of the medicinal plants, and to provide the high yield of essential oil.