Management Studies on Seed Production of Turf-Type Tall Fescue: II. Seed Yield Components

Information on how management affects seed yield components of turf-type tall fescue (Festuca arundinacea Schreber) cultivars is needed to improve cultural practices for seed production. We tested factorial combinations of two post-harvest residue managements (flailchopping or burning the stubble), two row spacing (0.3 and 0.6 m), three spring-applied N rates (100, 145, and 190 kg ha⁻), and three N application timings (double-ridge, spikelet initiation, and equally split between the two) on seed yield components of tuff-type cultivars Falcon, Rebel, and Bonanza, and the forage cultivar Fawn. Seed yields of all cultivars were closely correlated with the number of seeds produced per unit area (mS), but yields were weakly and negatively correlated with weight per seed. Compared with flail-chopping, burning the residue increased the numbers of fertile tillers, floret sites, and seeds per unit area in aH cultivars. The number of seeds per unit area was not affected by row spacing in Fawn and Bonanza, but was increased at 0.3-m row spacing in Falcon when the residue was burned, and was greater at 0.6-m in Rebel when the residue was flail-chopped. Increasing N rate above 100 kg ha-~ decreased floret site utilization and seeds per unit area in Fawn, but did not affect these components in Falcon and Rebel. Seeds per unit area in Bonanza was the greatest at 145 kg N ha 1. For all cuitivars, N application timing had little effect on seeds per unit area. We conclude that management practices for the turf-type cultivars should focus on maintaining a high number of fertile tillers throughout the stand life by burning post-harvest residue. Using narrower row spacings for early- and mid-maturing turf-type cultivars also could increase the number of fertile tillers per unit area when the post-harvest residue is burned. The optimum spring-applied N rate for seed production is apparently greater for the late-maturing turf types than for forage cuitivars. Contribution from Oregon Agric. Exp. Stn., Tech. Paper no. 11,139.