Conventional breeding of Greek oregano (Origanum vulgare ssp. hirtum) and development of improved cultivars for yield potential and essential oil quality

Abstract

This study is an attempt to describe a conventional breeding program on Greek oregano (Origanum vulgare ssp. hirtum). First of all, a descriptor list including the most significant morphological traits was developed for the starting genetic material. The program aimed to select the elite self-plants obtained from the initial population originated from Samothraki Island, in purpose to generate the ideotype of a new cultivar, characterized by desirable agronomical traits and qualitative properties. Therefore, a pedigree intraselection method, based on widely spaced single-plant performance through honeycomb arrangement, was applied. The existing genetic/phenotypic variability of plants and families produced after selection was evaluated for plant’s growth and biomass density, type of stems and inflorescences and their components of yield potential. In addition, the effect of the mode of pollination on plants’ performance from two types of families obtained from self (SP) and open pollination (OP) was assessed. The evaluation for the components of yield potential, the composition of essential oil and carvacrol content, was detected in selected self plants, revealing genotypes with high yield potential. The target of this breeding program was the selection for high essential oil and carvacrol content and stabilization of valuable herbage components. The main selection criteria; high carvacrol and essential oil content, dry weight of leaves and flowers, ratio of leaves and flowers per stem, were subjected to statistical analysis using analytic hierarchy process, and plants were ranking according to their performance. The end-scope of this research was to recombine or even improve the starting population of local population of Greek oregano, according to mean essential oil content and carvacrol, biomass production and uniformity in desirable yield components using efficient breeding and statistical tools of selection.