Aneuploidy in induced autotetraploid populations of festuca pratensis lolium multiflorum and lolium perenne iii. performance of plants at different sowing densities in a perennial sward of tetraploid festuca pratensis
Hereditas (Lund) 106(2): 277-288
The productivity of an induced tetraploid population of Festuca pratensis at different sowing densities displayed a typical yield-density response. There was a positive response in yield with increasing densities only early in the development of the sward. As the time passed, the variations in sowing densities were compensated by an altered growth made by individual plants. The mortality pattern of plants varied among seasons. During the establishing phase of the sward the mortality was not density dependent. The inferior ability of aneuploids to establish in the sward relative to the euploids was displayed by a higher mortality of aneuploids. As the plants had grown larger, the mortality of plants became density dependent. Competition started to affect the aneuploids earlier in the development of the sward than the euploids, reflected by a differential mortality pattern of aneuploids and euploids. The aneuploid frequency in the seed lot was 29.1%, and in the end of the experiment the aneuploid frequency was reduced to percentages ranging from 7.9% to 15.7%. The lower productivity of the aneuploids affected the yield only at the early stage of the sward development. Later, the surviving aneuploids were too few to influence the total yield.