This study was conducted in order to sustainable conservation and utilization of Trifolium genetic resources. A total of 1333 accessions of Trifolium under 32 species from 27 provinces were collected according to IPGRI descriptors. Collected germplasms are conserved in mid- and long-term conservation at National Plant Gene Bank of Iran. Statistical parameters of tendency to center and dispersion were estimated for 26 characters of samples collection site. The most collected germplasm related to T. pretense L., T. repens L. and T. resupinatum L. with 214, 188, and 142 accessions, respectively. Altitude related distribution of collection sites were differed from -21 m in Noshahar to 2850 m in Orumieh and Marand. The results revealed that over grazing and natural erosion were as the most important factors resulted in genetic erosion of Trifolium genetic resources in Iran. Whereas agriculture was not an effective factor on genetic erosion of clover landraces, because the farmers prefere to conserve their landraces. A few numbers of T. pretense, T. repens and T. resupinatum accessions were collected from saline sites. Distribution of clover species showed that West and North-West of the country could be considered as primary centers of clover genetic diversity in Iran.
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