Thirty-seven accessions (cultivars and populations) of M. sativa, M. varia and M. falcata (Medicago spp.) in a vegetative pot experiment and 46 accessions of Medicago spp. in a field experiment under natural infection were evaluated for Phoma medicaginis resistance at the Lithuanian Institute of Agriculture during 2008–2009. The results showed that the accessions possessed a broad range of partial resistance. The most resistant accessions had spring black stem and leaf spot (SBSLS) areas under the disease progress curve (AUDPC) values ranging within 429–868, whereas the most susceptible ones showed the AUDPC values of 2060–2650. All four disease severity evaluation values strongly correlated (r = 0.806**–0.968**) (*, **P < 0.05, 0.01) with the AUDPC values. Disease severity in 2008 strongly correlated (r = 0.906**) with AUDPC in 2009 under field conditions, whereas SBSLS AUDPC correlated weaker (r = 0.589**) with DS under pot conditions in 2008. Susceptibility to SBSLS was negatively strong and medium-correlating with pod setting (r = –0.716**), overwintering (r = –0.584*), crop rankness (r = –0.544*), grass yield (r = –0.576*) and stem thickness (r = –0.530*).

Keywords: Medicago, Phoma medicaginis, resistance, AUDPC