Seed-producing tillers of tall fescue develop in autumn and early winter. Consequently, the optimum time for autumn-sowing in Oregon is on or before 1 September (see Chapter 5). Tall fescue that is sown in October in Oregon often does not produce an economic seed crop the first year.
Crops sown in spring (April in Oregon) with or without a companion crop, or in summer without a companion crop, have resulted in good first harvest seed crops. Relatively high autumn N fertilizer inputs (100 kg N/ha) are also important to ensure that late sowings produce high seed yields.
In the milder North Island of New Zealand, three autumn sowing dates produced good seed yields of ‘Roa' and ‘Advance' tall fescues from March (early autumn) sowings, but 60% less seed yield from a mid-April sowing (Table 23-4). Similar results were obtained with another cultivar with monthly sowings in the first week of each month starting in October. Seed yields were similar through February, and then declined by 35% from a March sowing and by 74% from an April sowing (Hare, 1994a). In a cooler region of New Zealand, autumn sowing needed to be at least 4 wk earlier than in warmer regions to avoid yield loss from late sowings (Table 23-5).
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Hare (1994b) showed that 92% of Advance tall fescue seedheads had originated from tillers that had formed before the end of April (mid autumn). Virtually all the tillers produced over winter (June-September) were still vegetative at anthesis (i.e., flowers open, pollen being shed). Tall fescue plants need a long period of winter cold (at least 8 to 9 wk under 8°C) to produce an adequate reproductive head density.