|Keywords: ||Mentha piperita, Mentha arvensis var. piperascens, Lamiacea, Peppermint, Cornmint, Ecological agriculture, gamma-ray, irradiation, 60Co, essential oils, essential oil plants, Bulgaria|
In field experiments the effect of gamma irradiation with 60Co (in doses of 0.2, 0.5, 1, 2 and 5 kR) of mint and cornmint seedlings was studied.
We used cv Tundza and cv Zephir from Mentha piperita L. and cv Mentolna-14 from Mentha arvensis L. var. piperascence Malinv as experimental material.
The following were estimated: plant height, weight and branching, dry matter content, fresh herbage yield, content, yield and quality of essential oil, yield of rhizomes.
It was established that:
Treatment of the seedlings of cv Mentolna-14 with doses of 200, 500, 1000 and 2000 R increased fresh herbage yields with 11, 21, 17 and 9 % respectively, compared to the untreated variant.
Within cv Tundza, doses of 500 and 1000 R increased the yields with 11 and 32 % compared to the control.
Essential oil yield from cv Tundza increased by 10 %, with treatment doses of 1000 R. However, due to decreased oil content in the herbage in the irradiation treated plants, total oil yields decreased.
Irradiation of seedlings of cv Tundza with 200 and 1000 R increased menthol content in the oil.
Doses of 200, 500 and 1000 R increased the yield of rhizomes from cv Mentolna-14 by 12, 19 and 14 % respectively, compared to the untreated control.
Tundza increase of the rhizome yields by 11 and 23 was obtained as a result of irradiation with 500 and 100 R respectively.