EFFECTS OF SEED WEIGHT ON GROWTH, REPRODUCTION AND COMPETITIVE ABILITY OF LINUM-USITATISSIMUM SEEDLINGS

Two laboratory experiments were conducted to examine the effects of seed weight on growth, reproduction and competitive ability of Linum usitatissimum L. seedlings. In the first experiment, seedlings from light (3.5-4.0 mg), medium (5.0-5.5 mg) and heavy (6.0-6.5 mg) seeds were allowed to grow individually in pots for three or six weeks following germination. Seedlings from heavy and medium seeds were significantly larger than those from light seeds after growth of both three and six weeks. In the second experiment, seedlings from heavy (6.5-7.0 mg), medium (5.0-5.5 mg) and light (3.5-4.0 mg) seeds were allowed to grow for three months in pots either individually or in competition with one or three individuals of mustard (Sinapis alba L.). Increase in intensity of interference from the S. alba seedlings significantly reduced plant growth and number of flowers produced in each of the three seed size classes in L. usitatissimum. Seed weight did not affect final root or shoot biomass among seedlings with the same status of competitive conditions in any of the three competition treatments. In the same competitive conditions, seedlings from the heaviest seeds produced significantly more flowers than those from medium or light seeds. However, flax seedlings from the heaviest seeds grown in competition with three mustards did not produce more flowers than seedlings from lighter seeds grown in competition with only one mustard or free of interference.