Assessing Genetic Reserves in Sicily (Italy): the Brassica Wild Relatives Case Study

The Brassica genus, belonging to the Brassicaceae, represents one of the most complex genera used in the vegetable industry. As many as 320 taxa (species, varieties, con-varieties, subspecies and cultigen groups) are included in the genus and a number of them are widely used as important sources of vegetables, condiments, and both edible and industrial oils. The ancestors of modern cultivated Brassicas have been used in the past in human diet, and they are still harvested in the wild in some countries. The elucidation of the origin of crops of B. oleracea L. is still an important research task. Studies of DNA olymorphisms suggested a monophyletic origin (Song et al., 1988), whereas for other authors the domestication of several cultigen groups of B. oleracea is polyphyletic and is strictly related to several wild Brassica ancestors that represent a common complex gene pool (Snogerup et al., 1990). The latter assumed that a number of crops, widespread from the European Atlantic coast to the North Sea, originated from B. oleracea subsp. oleracea, while recent studies using molecular genetic marker evidenced a strong divergence among Mediterranean Brassica wild species and the B. oleracea wild type occurrences of northern European Atlantic coasts. It was concluded that the domestication of B. oleracea cultigen groups occurred along the Greek-speaking area of Mediterranean basin (Mitchell, 1976; Maggioni et al., 2010). The origin of cauliflower and broccoli from B. oleracea group seems to be located in the mentioned area and is linked to B. cretica, B. incana, B. insularis, B. macrocarpa, B. montana, B. rupestris and B. villosa as wild relatives (Gòmez-Campo and Gustafsson, 1991). These species are perennial with a woody stem, up to 1.5 m tall, large leaves and high glucosinolate content; they are diploid (2n = 18), often self- incompatible, with high tendency to mutations, and freely crosspollinate among them and with B. oleracea crops grown in the surroundings. Brassica wild relatives have been extensively used for more than a century to increase resistance/tolerance to biotic and abiotic stress resistance of the crops. Recently, high antioxidant properties were found in some Sicilian broccoli landraces. The use of Sicilian broccoli landraces and wild relative species in breeding allowed obtaining new cultivars with high levels of glucosinolate (Mithen et al., 2003). Sicilian occurrences of crop wild relatives (CWR) were further investigated within the work package 'Case Study Brassica' of the targeted action AGRI GEN RES 057 (AEGRO, 2011).