The natural growth habit of creeping red fescue (Festuca rubra L. var. rubra) involves a steady proliferation of tillers which eventually become too dense to form seedheads. The effects of the initial density (1.6, 3.1, 6.3, 12.5, 25, 50 and 100 plants m−2) and row spacing (20, 40 and 80 cm) on reproductive components and seed characteristics of red fescue were studied in a northerly environment for three production years (1991–1993) The weight proportion of cleaned to uncleaned seed decreased as density increased, from 82% at 1.6 plants m−2 to 60% at 100 plants m−2. The thousand-seed weight was 1.20–1.54 g (i.e., 830 000–650 000 seeds kg−1) and decreased as density increased. The specific seed weight was 16–25 kg hL−1; it differed among years and decreased as density increased. The germination capacity of the seed was unaffected by density but differed among years, averaging 87, 92 and 69% in the three consecutive production years. The seed yield per plant, the number of seedheads per plant, and the number of seeds per plant decreased exponentially as the density increased. The number of seeds per seedhead decreased as density increased in the first year but was less affected subsequently, except in the third year at 50 and 100 plants m−2 on 20-cm rows, when no seeds were matured. The seed yield was correlated closely with the number of seedheads per square metre, which increased with density in the first year but decreased as density increased in the two subsequent years. A relatively high density of well-spaced plants is required at establishment to optimize seedhead formation in the first crop but is detrimental to seedhead formation and seed yield subsequently. Key words: Red fescue; Festuca rubra var. rubra, population density, plant and row spacing, yield components, seed quality
Ploidy and cultivar group differences in the thousand-seed weight of red fescue (Festuca rubra L.)