Can Glandular Hair Density be a Breeding Marker for Origanum Vulgare subsp. Hirtum with High Essential Oil Content?

Abstract

Origanum vulgare subsp. hirtum (Link) Ietswaart is an essential oil rich plant traditionally used as oregano. Based on the interest of the essential oil producing sector, in 2000 we have started a breeding program of O. vulgare subsp. hirtum. Plant material for our breeding work consists of 6 progeny. Individual evaluation of the plant material was carried out in 2008-2009 with the primary aim of finding mother plants with appropriate morphological features, high essential oil content (> 7%) and with carvacrol as the main essential oil component. Among the survey of morphological characteristics special attention was given to glandular hair density in order to test the usability of it as a morphological marker for screening progeny for high essential oil content. The characteristics of the progeny can be described with high variability ensuring the possibility of a good selection base. Evaluating the morphology, essential oil content and constitution of the individuals, 20 plants were selected on the grounds of their high (7-8.6%) essential oil content, high ratio (70-93%) of carvacrol in the essential oil and typical morphological features of O. vulgare subsp. hirtum. From the results of glandular hair density it can be stated that the correlation between glandular hair density of the upper, middle and lower leaves either on vegetative or generative shoots and essential oil content was never strong enough (correlation coefficient < or = 0.5) to use it exclusively as a morphological marker for individual selection.