Meiosis and fertility in spontaneous tetraploids of Festuca pratensis [Huds.]

The paper is the second part of the studies on spontaneous tetraploids of Festuca pratensis, morphological characters of which were given in the previous article (WIŚNIEWSKA 1994). This paper deals with meiosis in PMCs of spontaneous tetraploids of Festuca pratensis and their F₁ progeny (2n=28) and describes the fertility of these plants in comparison to that of the colchitetraploid cv. Westa and diploid cv. Skrzeszowicka. Different chromosome parings were found in three spontaneous tetraploids. In tetraploid 4/2, most frequently quidrivalents (5.72 IV per 1 PMC) were observed, whereas in tetraploids 465/2 and 534/2, bivalents were prevailing (5.36 and 5.65 II per cell, respectively). The rest of chromosomes remained as univalents, formed trivalcnts and uncountable chromosome associations. Spontaneous tetraploid plants had dehiscent anthers and a high pollen grain fertility (from 78.0 to 94.5%). The degree of seed setting at self-pollination in these plants was low. However, at open pollination, they set a little less seeds than the diploid cv. Skrzeszowicka and the cv. Westa. The plant Si obtained from selfed of spontaneus tetraploids were all tetraploids (2n=28). Seeds obtained from open pollination of spontaneous tetraploids, gave rise to 160 plants of F₁ and all were also tetraploid. No large differences in chromosome pairing.were observed in plants of F₁. At metaphase I a predominant number of bivalents (from 4.72 to 6.05 II) and a smaller number of quadrivalents (from 3.96 to 4.63 IV), were observed. All the plants of F₁ and S₁ generations had dehiscent anthers. Pollen grain viability of Fi plants was high (88.0-90.0%) and similar to that of the parental forms (78.0-89.5%) in the same year of the studies. The average seed setting of all studied F₁ plants at self-pollination ranged from 0.15 to 0.22%, being lower than that of the parental forms. At open pollination it ranged from 34.2 to 36.0%, which was higher than or similar to that of the parental forms in the same year.