Wild seakale (Crambe maritima L.) diversity as investigated by morphological and RAPD markers

Seakale is a Brassicaceae, native to the coastal sands of Northwestern Europe. To bring this species closer to commercialisation and thereby enhance the diversification of vegetable crops, a breeding program was initiated in 1992. A systematic search for wild populations was undertaken in France, from Quiberon (south Brittany) to Dunkerque (north France near Belgium) to enlarge its genetic basis. Many sites previously described in the literature have disappeared, while five large sites, not previously described, were found. Morphological descriptors and molecular markers (RAPD) were used to study the phenotypic and phenetic variability of the collected plants. A great variability for leaf and leaf-stalk colour, limb, flowers and siliques sizes, was observed. Among the wild collected plants, molecular similarity varied from 25 to 85%. The mean distance from all the wild genotypes to the breeding material already in collection was large (50%). Even if no clear correlation was found between morphological assessment and molecular data except for the leaf-stalk descriptor, the collecting trip was a success. A real enlargement of the variability was obtained.