Evaluation of parsley (Petroselinum crispum) germplasm diversity from the Greek Gene Bank using morphological, molecular and metabolic markers

Parsley (Petroselinum crispum) aromatic, edible leaves are used fresh or dried as a herb, but also for their pharmaceutical properties. Given the profound concern to high nutritious and pharmaceutical value of superior plant's germplasm, a survey is presented in this study on the phenotypic, genetic and phytochemical characterization of fifteen Greek parsley landraces in comparison to nine commercial cultivars, all grown under the same conditions in Greece. Our data reported high differences between the Greek landraces and most of the commercial cultivars in a majority of morphological traits investigated according to the International Union for the Protection of New Varieties of Plants descriptors list. The genetic diversity of all landraces and commercial cultivars were investigated using Inter Simple Sequence Repeat and Amplified Fragment Length Polymorphism molecular markers. The percentage of polymorphic loci was 63.83 % for the cultivars, and all loci were polymorphic (100 %) for the Greek landraces, while considerably higher values of unbiased haploid gene diversity were revealed in the landraces compared with the commercial cultivars. The essential oil yield of the landraces and cultivars of parsley studied ranged from 0.11-0.26 mL 100 g-1 leaf FW. The major compounds in the parsley essential oils as determined by gas-chromatography were alpha-pinene (0.6-11.8%), beta-pinene (0.2-8.2%), myrcene (1.3-13.5%), beta-phellandrene (9.6-39.1 %), terpinolene (1.4-8.9 %), 1, 3, 8-p-menthatriene (0.1-43.4 %), ciscarveol (0.2-8.1 %), iso-dihydro carveol acetate (0.2-6.9 %), myristicin (0.51-44.4%) and apiole (0.01-35.2 %). According to the targeted liquid chromatographic analysis coumarin derivatives, hydrocinnamic acids, flavanones, flavones and flavonols were identified in parsley methanolic extracts. Flavones were represented by apigenin and luteolin derivatives, and flavonols by kaempferol, quercetin, galangin and morin. Apiin was the major flavone in all parsley samples ranging from 1732.57 to 3676.43 mg 100 g -1 dry weight. The wide variation in phenotypic, genetic and phytochemical profiles observed for the landraces, indicate that the Greek germplasm collection could serve as an important source of genetic material for plant breeding and selection towards the development of new cultivars with superior traits regarding their aroma quality and polyphenolic content but also to support ongoing studies on flavonoid biosynthesis in this culinary herb.