The evaluation of the variability of morphological and chemical traits of the selected lemon balm (Melissa officinalis L.) genotypes

Abstract

In the experiment done in 2009–2011, 22 selected lemon balm genotypes originating from European botanical gardens were tested. The obtained results showed that the objects in lemon balm collections varied in terms of all tested traits. The number of lateral shoots ranged from 16.6 (Oxford) to 38.5 (Bayreuth). The length of the leaf was from 3.68cm (Göttingen) to 5.71cm (Tabor) and its width oscillated from 2.82cm (Göttingen) to 4.42cm (Vactratot). The internode length varied from 2.18cm (Debrecen) to 4.03cm (Prague). The dry weight of the herb ranged from 157.0g (Bratislava1) to 339.3g (Vacratot). The seed yield oscillated from 22g (Bratislava1) to 182g (Bonn) and the weight of 1000 seeds was from 0.356g (Bratislava1) to 0.632g (Vacratot). Essential oil content oscillated from 0.05% (Padova) to 0.44% (Warsaw). Citral, citronellal and caryophyllene were the main compounds of lemon balm essential oil. The following traits had a positive effect on the dry herb yield: the number of lateral shoots per plant and the leaf length. The aim of the multidimensional analysis was to compare lemon balm objects in respect of eight morphological traits and yielding simultaneously.The evaluation of lemon balm genotypes will make it possible to choose appropriate genotypes for further breeding program.