Meiosis in haploid sugar beets (Beta vulgaris L.) obtained in in vitro-cultures
1991
Szota, M. | Goska, M. (Institute of Plant Breeding and Acclimatization, Bydgoszcz (Poland). Dept. in Bydgoszcz)
The course of meiosis was studied in 9 haploid sugar beets obtained from unfertilized ovules. A partial conjugation of chromosomes and structures similar to chiasmata were observed at prophase stages. At MI the most frequent were configurations 9I, 7I 1II and 5I 2II. Secondary chromosome associations of the end-to-end, side-to-side and end-to-side type as well as sporadically polyvalents covering 5, 6 and 8 chromosomes were observed. No distinct boundary has been found between the stages MI and AI. In the further studies there occurred irregularities of precocious division of univalents, lagging chromosomes, bridges and unequal separation of chromosomes to the poles. There also occurred dyads, trials and polyads with spores of different size and with numerous microspores, as well as monads. Pollen was differentiated as to the grain size and was little viable. Irregularities of meiosis cause almost complete sterility of haploids
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