EFFECT OF PHENOLOGICAL STAGES ON PLANT DRY-MATTER PARTITIONING AND SEED PRODUCTION IN BERSEEM (TRIFOLIUM-ALEXANDRINUM L)

Berseem clover (Trifolium alexandrinum L.) is an annual forage crop wi dely grown in Mediterranean environments. Dry matter partitioning in t he leaf, stem and root and seed production of three populations of Egy ptian as well as Italian origin were evaluated under four cutting regi mes. The cutting treatments were applied to the plants at different st ages of plant development: at the fourth (A) and eighth nodes elongati on (B), at early flowering (C) and physiological maturity of seeds (D) . After herbage, harvest plants were utilized for seed yield and evalu ation of its seed yield components. Higher dry matter and seed yield w as obtained in treatments D and B, respectively. In the other treatmen ts, dry matter content was lower than in treatment D and related to th e phenological development of the plant Dry matter content in the root was higher when the cut was applied at early flowering Cutting regime s influenced plant mortality, with the number of dead plants increasin g from the cut applied in early (A) to that in the final treatment (D) . Cuts applied at early stage of development depleted root reserves ca using plant death. This peculiarity could be a tool for selecting popu lations with higher persistence and with a more tolerant physiological response to stress imposed by cuts. The populations of Egyptian origi n, in comparison with the Italian ones, were more productive in dry ma tter in the early stage of growth and in all treatments were higher in seed weight.