Influence of Seed Size and Depth of Sowing on the Establishment and Growth of Varieties of Fiber and Oil Seed Flax

Small, medium, and large seeds were selected from commercial samples of three oil‐seed and three fiber flaxes (Linum usitatissimum). The varieties were themselves chosen to represent a wide range of seed sizes. In early seedling development both leaf area and dry weight were closely related to seed size, and varietal differences were later imposed on this relationship. Varietal differences in hypocotyl length appeared particularly early. Seedlings from small seeds emerged fastest from shallow (1 cm) and those from large seed from deep sowing (6 cm) irrespective of variety. Seed samples of some varieties contained a sufficient range of seed for some to find their optimum at shallow and others at deep sowing. Advantages of seed size were not generally maintained when plants were grown under the normal density stress of a crop — though significantly taller plants were obtained from the large seeds.