Meiosis and fertility of spontaneous triploid of white sweetclover (Melilotus albus Med.)
1988
Kazimierski, T. | Kazimierska, E.M. (Polish Academy of Sciences, Poznan (Poland). Inst. of Plant Genetics)
Meiosis and microsporogenesis in spontaneous triploid form of white sweetclover (2n=24) have been studied. At metaphase 1 the chromosomes were linked in trivalents, bivalents, rarely a single quadri-, penta- and hexavalent were encountered, and part of the chromosomes occurred as univalents. In 1/5 of analysed cells all the chromosomes were linked in trivalents. One cell averagely contained: 6.65(3), 1.27(2), 1.74(1), 0.020(4), 0.012(5) and 0.022(6). A large number of trivalents in a cell suggests that the studied triploid is an autotriploid form. The first and second divisions proceeded irregularly. In the process of microsporogenesis tetrads of microspores and tetrads with minimicrospores were formed. The chromosome number in the pollen grains during the first mitosis ranged from 9 to 13. In a considerable part of grains after the first mitosis there occurred two vegetative nuclei instead of a vegetative and generative nucleus. A triploid form was characterized by a low extent of fertility. A 20.6 percent viability of pollen grain was noted
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