EFFECT OF NITROGEN FERTILIZATION ON SEED PRODUCTION OF Lolium perenne L. TURFGRASS CULTIVARS

The paper contains the results of field and laboratory experiments on three Lolium perenne L. turfgrass cultivars (Gazon, Nira and Sandra) at Malopolska Plant Breeding Station (HBP) in Skrzeszowice near Krakow (220 m a.s.l.) conducted in the years 2006-2008. The analyses assessed the effect of doses of mineral fertilization with nitrogen (60, 90 and 120 kg N.ha(-1)) applied at early spring, the start of the earing stage and autumn on the seed yield. The highest yield was monitored by the inflorescence shoot density of cv. Nira (1895 shoots/m(2)), cv. Gazon (1976 shoots/m2) and cv. Sandra (2098 shoots/m(2)). Fertilization dose of 90 kg N.ha(-1) applied three times effected the most considerably the number of spikelets per ear and the efficiency of seed settling on the ear: from 73 % (cv. Nira) to 76 % (cv. Sandra). The highest seed yield was obtained as a result of the 120 kg N.ha(-1) fertilizations applied three times.