A Contribution to the study of the distribution ofMedicago-Sinorhizobiumsymbiosis in Sardinia (Italy)

The paper summarizes the results of aMedicago-Sinorhizobiumgermplasm survey and collection carried out in the island of Sardinia (Italy) in 1998/99 and subsequent laboratory isolation of microbial strains, soil sample analyses and determination ofMedicagospecies. According to a stratified sampling methodology, the major ecological characteristics of island's habitats were taken into account, collecting and surveying mostly in natural or semi-natural habitats (no roadside sites nor cultivated fields were sampled). Forty-six sites, widely distributed in semi-natural representative areas of Sardinia, ranging from sea level to above 1000 m asl, were sampled and 24 were surveyed to gather additional data on species distribution. Root nodules were collected from 15 species (13 annuals) out of the total 21Medicagospecies recorded in Sardinia. Isolation of root nodule bacteria accessions and identification of 29 strains were achieved. A total number of 17 species were surveyed and mapped. The present study gives a first contribution to the knowledge of the present distribution of the species of the genusMedicagoin Sardinia with special concern to the species recorded or sampled during the survey and highlights the presence ofMedicagobiodiversity hot spots.