EFFECT OF HARVESTING TIME ON A FORAGE YIELD VARIETY AND A SUNFLOWER (HELIANTHUS-ANNUUS, L) HYBRID

The effect of a variety and sunflower hybrid and I three harvesting ti mes for forage production in a ferrallitic red soil according to a 2 x 3 factorial design in random blocks with four replications was studie d. The treatments evaluated a local variety and a ED 6540 hybrid and t hree harvesting times (buds, 5% and 50% flowering) in forage yield. An interaction between the hybrid, variety and harvest time for height, number of plants/m(2), percentage of total leaf yield, stems and flowe rs, DM yield of the stem, crude protein and whole plant was found. The plants were taller (232 cm) and more plants/m(2) (8.7) were found in the local variety when harvesting at 50% flowering. The percentage of dry matter of leaves, stems, flowers and the whole plant was higher in the local variety than in the hybrid when harvesting occurred at 50% flowering. Yield was higher (P < 0.001) in the local variety (74.8 kg DM/ha/day) than with the hybrid (34 kg DM/ha/day). The best harvest ti me for yield was when the plants were cut at 50% flowering (67.9 kg DM /ha/day). There was an interaction between the local variety, the hybr id and harvest time for forage yield and crude protein (P < 0.01). How ever, forage production (8.61 and 3.11 t/ha DM) was greater when harve sting was at 50% flowering in the variety and hybrid, respectively. In general, the hybrid offered a greater CP percentage than the variety. The local variety harvested at 50% flowering was less expensive (16 C uban pesos). It is concluded that the highest forage and protein yield s and the lowest cost per t of forage produced were obtained with the local variety cut at 50% flowering. The ED 6540 hybrid should not be u sed as forage.