Phenotypic diversity of Greek dill (Anethum graveolens L.) landraces

Dill has multiple culinary and medicinal purposes and the use of their landraces into a plant
breeding program, requires the analysis of their phenotypic diversity. In this study, 33 Greek dill
landraces collected from diverse areas were evaluated using traits based on UPOV descriptor list.
Phenotypic diversity was assessed using Shannon-Weaver diversity index (H΄) and non-linear
principal component analysis. Grouping of landraces was further performed through hierarchical
cluster analysis. The H’ index ranged from 0.32 (stem waxiness) to 0.98 (density of foliage) with a
mean value of 0.68 indicating a high level of phenotypic diversity. High H’ values were recorded
for the foliage width, stem color and anthocyanin coloration. Multivariate analysis revealed three
common genetic groups: 1) North mainland Greece, 2) Aegean islands and 3) Central mainland
Greece. The landraces’ heterogeneity was attributed to various traits linked to specific
geographic origin, such as early time of flowering and high stem waxiness allied with the
landraces originated from the Aegean islands. Greek dill landraces revealed useful variation on
yield component traits related to fresh herb weight and to seed production, such as high
number of leaves/plant and large diameter of main umbel that can be promptly exploited in
breeding programs.