DISTRIBUTION, DIVERSITY AND POTENTIAL AGRONOMIC VALUE OF MEDICAGO-POLYMORPHA IN SARDINIA

Thirty-five populations of Medicago polymorpha were collected from thr oughout Sardinia (Italy) in 1989 with a view to developing pasture spe cies suitable for improving degraded grasslands in the northern Medite rranean basin. Herbage and seed production were compared with the Aust ralian cultivar, Circle Valley, over 2 years at Bonassai, north Sardin ia. Regeneration in the 2 years after sowing and seed size were also e stimated. All variables were related to collection site parameters usi ng multivariate analysis. Herbage production varied between 2 and 8 t dry matter/ha, and up to 1.5 t/ha of seed was produced, K-means cluste ring of agronomic and morphological variables indicated that there wer e two groups present; one similar to variety polymorpha and one to var iety vulgaris. There were two other single entry clusters, one of whic h contained cv. Circle Valley. Principal component analysis of the env ironmental variables indicated that cluster 1 (vulgaris) was more like ly to come from mountainous areas where winter temperatures are low, a nd cluster 2 (polymorpha) from coastal areas where temperatures are mi ld. Regeneration of cluster 1 was better than that of cluster 2, which in turn was better than Circle Valley, indicating that populations in cluster 1 are better adapted to the management system imposed at Bona ssai. The results indicate that M. polymorpha has considerable potenti al to improve the grasslands of Sardinia. However, it is unlikely that imported cultivars will be successful, and it seems important that th e selection of local populations should continue. Commercial seed prod uction in Sardinia is likely to be a problem, and grazing management u nder the conditions of communal ownership may have to be reviewed. It is important that future research and development involves farmers and other industry groups.