Evaluation of berseem clover (Trifolium alexandrinum L.) germplasm in Sardinia, Italy

Berseem clover (Trifolium alexandrinum L.) is an annual forage legume largely cultivated in central, southern and insular regions of Italy. Sacromonte was the Miskawi-type variety widespread in the country for decades, while in recent years several new varieties have been released. This study aimed at: (i) acquiring greater knowledge on forage and seed yields of a set of varieties grown in two consecutive years (October-July cycle) in a Mediterranean environment of Sardinia; and (ii) evaluating three experimental strains originating from traditional germplasm. Although with marked differences among varieties and between years, berseem clover proved to be a valuable forage resource, with great potential of exploitation also during the cold season. Under the current, moderately favourable rainfed conditions (> 160 mm spring rainfall), the best materials were also able to provide good seed yield with no supplemental irrigation and after an intensive forage exploitation of the crop. The oldest variety Sacromonte still proved the best performing variety for forage yield across years. Results of some newly released varieties were not as satisfactory, suggesting that the adopted selection criteria and/or the selection environments were not fully appropriate for the test conditions, which are not uncommon in peninsular and insular regions of Italy. On the other hand, the trend towards higher yield levels of one experimental strain as effect of specific adaptation to the growing environment, and the outstanding seed yield of the two other experimental strains, which had also been selected for this trait, suggest that some selection gain may still be possible from traditional germplasm targeting well-defined growing environments and adopting specific selection criteria.