Effect of seed rate and row spacing in seed production of Festulolium

Festulolium (xFestulolium) is a cross between the two species fescue (Festuca L.) and ryegrass (Lolium L.) and is a promising forage and seed crop. To stimulate the production of Danish organic festulolium seeds a three-year field experiment was performed from 1999 to 2002 in a ryegrass-type festulolium, Paulita, and in a fescue-type festulolium, Hykor. The objectives were to examine the influence of row spacing (12, 24, and 36 cm) and seed rate (8, 12, or 16 kg ha-1) on plant establishment, development, and seed yield. Observations of autumn and spring in-row plant densities indicated satisfactory plant establishment in all combinations of seed rate and row spacing. The number of reproductive tillers was in the range from 800 to 2200 m-2 in Paulita and from 500 to 1300 m-2 in Hykor. Row spacing had an effect on the number of reproductive tillers and in both cultivars the highest number was achieved at 12-cm row spacing. Seed yields in the Italian ryegrass type averaged from 1050 to 1150 kg ha-1 and in the tall fescue type from 650 to 800 kg ha-1. Doubling row spacing from 12 to 24 cm had no effect on seed yield in Hykor, while a further increase of row spacing to 36 cm showed a decrease in seed yield. No effect of row spacing on seed yield was observed in Paulita. Neither of the two types was affected in seed yield by seed rate. The fact that row spacing in both types can be increased to 24 cm without having a concomitant negative effect on seed yield implies that mechanical weed control is an optional management technique. Therefore our results have important implications in/for organic grass-seed production.