Molecular Relationships and Genetic Diversity Analysis of Venetian Radicchio (Leaf Chicory, Cichorium intybus subsp. intybus var. sylvestre, 2n = 2x = 18) Biotypes

Abstract

Chicory (Cichorium intybus L., 2n = 2x = 18) is naturalized and grows wild in many parts of Europe, South and Central Asia and N. Africa; moreover, this plant is an important leafy vegetable cultivated worldwide. In Italy, this horticultural crop is known as radicchio, and different biotypes of this crop are cultivated, especially in the north-eastern part of the Italian Peninsula. Known to be introduced in and cultivated since the 17th century in the Venice area, the original biotype, still cultivated and named “Late Red of Treviso”, differentiated over the centuries, and it was also hybridized with endive (C. endivia), giving origin to many other biotypes. Several studies, based on morphological characterizations and historical reports, describe the relationships between the most popular cultivated local varieties of this species, but this work, focused on the use of molecular marker information obtained through DNA fingerprinting, presents validations and new insights into the genetic relatedness and diversity of these biotypes. By means of random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) molecular markers, this study provides insights into the genetic relationship that intercourses among the five most important local biotypes historically cultivated in the Veneto region, which is also the geographic centre of differentiation of this cultivated leafy vegetable. Through the construction of a maximum-likelihood dendrogram and the reconstruction of the genetic structure of a core collection, consisting of 652 samples belonging to five biotypes of radicchio divided into 22 old farmer populations, original data on their genetic origin, distinctiveness, relatedness and differentiation are reported and discussed.