Crop density and seed production of tall fescue (Festuca arundinacea Schreber). 2. Reproductive components and seed characteristics

Abstract

The population density and spatial arrangement of plants may influence the productive life and performance characteristics of a perennial grass-seed crop. A study was conducted to determine 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) of plants on reproductive yield components and seed characteristics of tall fescue (Festuca arundinacea Schreber), over 3 consecutive production years (1991–1993) in the Peace region of Canada. The weight proportion of cleaned-to-uncleaned seed was 85–86% for the three lowest plant densities and then decreased, as density increased, to 82% at 12.5 plants m−2 and 66% at 100 plants m−2. The 1000-seed weight decreased as density increased and ranged from 1.68 to 2.22 g (i.e., 595 000 to 450 000 seeds kg−1). The specific seed weight ranged from 18 to 31 kg hL−1; it differed among years, but the effect of plant density was inconsistent. The germination capacity of the seed was unaffected by plant density, but differed among years; it averaged 87%, 88% and 59% in 1991, 1992 and 1993, respectively. The seed yield/plant, the number of panicles/plant, and the number of seeds/plant decreased exponentially as plant density increased. The number of clean seeds/panicle decreased, as plant density increased, in the first year but was less affected subsequently, particularly with the 20-cm row spacing. The seed yield was correlated closely with the number of panicles m−2 (r = 0.659***). An initial density no greater than 25 plants m−2 in rows spaced 20–40 cm apart enhanced seed quality by producing a greater proportion of clean seed which had a higher 1000-seed weight. Such a plant density, however, is at the low end of the optimum range for maximizing seed yield per unit land area. Key words: Tall fescue, Festuca arundinacea Schreber, population density, plant and row spacing, yield components, seed quality