A field study was conducted with tall fescue (Festuca arundinacea Schreber) to determine the effect of the initial population density and spatial arrangement of plants on crop development and seed yield. Individual seedling plants were transplanted at seven densities (1.6, 3.1, 6.3, 12.5, 25, 50, and 100 plants m−2) and three row spacings (20, 40, and 80 cm), and characteristics of seed production were determined for 3 yr (1991–1993). Over the 3 yr, heading commenced at dates differing by 15 d and was delayed, as density increased, by 8, 6, and 2 d, respectively, in the first, second, and third production years. The time of seed maturity differed among years (21 July to 4 August) but was generally unaffected by density or row spacing. In the first production year, seed yield increased with density up to 25 plants m−2 for each row spacing, then remained constant to at least 50 plants m−2 with both 20- or 40-cm rows; it decreased slightly at 100 plants m−2 with 20 cm rows. In the second production year, seed yield was relatively independent of plant density except that it decreased when the initial density was less than 6 plants m−2 with a row spacing of 80 cm, and tended to be greatest with the 40-cm row spacing at 6–25 plants m−2. In the third production year, seed yield was much lower than in the previous 2 yr but the pattern of response to the density and row spacing treatments was similar to that in the second production year. The seed yield of tall fescue can be optimized for at least 3 consecutive years by establishing an initial density of 20–100 plants m−2 in rows spaced 20–60 cm apart. If the maximization of first-year seed yield is a priority, then the initial establishment should be at a density of 25–50 plants m−2 in rows spaced 20–40 cm apart. Key words: Tall fescue, Festuca arundinacea Schreber, population density, plant spacing, seed production
Photosynthetic properties of elite erect leaf maize inbred lines and their contribution to seed production improvement
