| Abstract: | Crop management influences considerably the three components of grain yield, growth duration, growth rate, and harvest index (HI). Effects of seeding rate on these yield components in oats ( Avena sativa L.) was assessed in field experiments at the Viikki Experimental Farm, University of Helsinki, Finland (60°13'N) in 1991 and 1992. Three Finnish oat genotypes were evaluated; a long-strawed landrace cultivar, a moderately long-strawed modern cultivar, and a semi-dwarf breeding line. The following traits were measured: grain yield, days from sowing to yellow ripeness, number of tillers on main shoot, phytomass, vegetative phytomass, and their growth rates (PGR and VGR, respectively), panicle weight and its filling rate (PFR), HI, leaf area index (LAI), and at intervals, dry-matter accumulation in leaves and straw.
Increases in seeding rate significantly decreased growth duration and PGR of individual plants but increased PGR on a ground area basis. Seeding rate did not, however, affect HI. When seeding rate was increased from 200 seeds m?2 to 500 seeds m?2, reductions in vegetative phytomass, panicle weight, VGR, and PFR for individual plants ranged between 20 and 40 %, depending on genotype. At ≥600 seeds m?2 differences in these components between seeding rates were modest. However, PGR, VGR, and PFR per unit ground area increased with increasing seeding rates up to 600–700 seeds m?2. Moreover, the higher the seeding rate, the higher the peak LAI (2.7 maximum) and the earlier the canopy closure. Hence, our results showed that a seeding rate of 600–700 seeds m?2, which resulted in uniculm growth habit, is advantageous in terms of grain yield at high latitudes due to higher biomass accumulation and subsequently greater interception of PAR. |
