Genetic diversity and differentiation in Patellifolia (Amaranthaceae) in the Macaronesian archipelagos and the Iberian Peninsula and implications for genetic conservation programmes

This is the first comprehensive investigation of the patterns of genetic diversity of Patellifolia species. The main objective of our research work is to determine Most Appropriate crop Wild relative Populations (MAWP) suited to conserve in situ wild relatives of the sugar beet. Individual plant samples of P. patellaris were collected at 26 and of P. procumbens/P. webbiana at seven sites and analysed with 24 and 22 microsatellite markers, respectively. On average 15 alleles per locus were found within the set of 581 P. patellaris and an average of 12 alleles per locus in the set of 172 P. procumbens/P. webbiana individuals. The factorial analysis showed diversity patterns which agree well with the geographic origin of the samples. The genetic data suggest that P. patellaris reproduces mainly by self-fertilisation while P. procumbens/P. webbiana have the signature of out-breeders. The measure Δ was used to calculate the genetic distance of each occurrence to the pooled remaining occurrences, the complement. Occurrences with either the lowest or the highest genetic distance to the complement are particularly suited to conserve the genetic diversity of the species. Eight occurrences of P. patellaris , two of P . procumbens and one for P. webbiana were determined according to this scheme, proposed as MAWP and recommended for the establishment of genetic reserves.