Streszczenie. The study determined the morphological and genetic diversity among nine cultivars of peppermint (Mentha × piperita L.): ‘Almira’, ‘Asia’, ‘Chocolate’, ‘Citaro’, ‘Granada’, ‘Grapefruit’, ‘Multimentha’, ‘Swiss’ and ‘Variegata’. The leaves of the peppermint cultivars were characterized by substantial variation in morphology and size. The leaves of ‘Multimenth’, ‘Grapefruit‘ and ‘Swiss’ were largest, and those of ‘Swiss’ were considerably elongated. The ‘Almira’ cultivar had the smallest leaves. Although similar leaf morphology was observed in ‘Asia’, ‘Citaro’ and ‘Chocolate’, in ‘Grapefruit’ and ‘Multimentha’ and in ‘Swiss’ and ‘Variegata’, no two cultivars were the same in this respect. Differentiation of tested peppermint cultivars were also confirmed at genetic level. Genetic diversity among tested cultivars ranged from 0.388 to 0.846. The most different were cultivars Almira and Citaro.

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