Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacky University in Olomouc and Gene Bank Department - Workplace Olomouc, Research Institute of Crop Pr oduction in Prague, Czech Republic, conducted an expedition in seven Europe an countries (Austria, Czech Republic, France, Germany, Italy, the Netherla nds, Switzerland) in August/September 1999 to collect wild Lactuca spp. ger mplasm and study its geographic distribution, ecology and biodiversity. Dur ing the mission, more than 600 locations were visited resulting in the coll ection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. se rriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chond rilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Repub lic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were co llected. The most characteristic habitats with a high density of Lactuca sp p. populations were observed along roads and highways, grassy ditches, rude ral communities, and dust-heaps. Natural infections by powdery mildew (Erys iphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribu tion, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuc a spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processe s, and genetic variability of host-parasite interactions.