EFFECT OF SEED SIZE ON SEEDLING VIGOR AND FORAGE PRODUCTION OF WINTER-WHEAT

There are numerous reports of increased wheat (Triticum aestivum L.) g rain yields with large seed compared with small, but these do not rela te to use of wheat for grazing purposes. Field experiments were conduc ted over 3 yr to measure the effect of seed size on stands, percentage ground cover, and fall and spring forage production. Other variables included sowing plots by seed number or volume per unit area. When sow n at the same number of seed per square metre (220), large (> 0.24-cm diameter) seed resulted in 16-74% more plants per area than small (< 0 .20-cm) diameter seed. When sown by volume (8.7 mL m(-2)), stands from small seed were similar to or more dense than those from large seed. When sown by seed number, large seed increased fall ground cover by 58 -100% over small seed; however, even when sown by volume, large seed i ncreased ground cover by 13-26%. Similarly, when seeded on an equal-nu mber basis, large seed increased fall and spring forage 23-214% over t hat produced by small seed. Although sowing on an equal-volume basis r esulted in fewer significant differences among seed sizes, large seed produced 35% more fall forage one year and 44% more spring forage anot her year. Therefore, sowing large seed should help reduce soil erosion by producing plants with greater ground cover. Similarly, large seed should increase the amount of forage for producers who sow winter whea t early as a prelude to grazing livestock.