Karyological methods of ploidy level determination in sugar beet varieties
1995
Tomaskova, D. (Vyzkumny Ustav Rostlinne Vyroby, Prague-Ruzyne (Czech Republic)) | Dobiasova, B.
In order to check ploidy level in sugar beet varieties, two karyological methods for counting of chromosomes were proved. Firstly, actively growing roots were collected and pretreated with para-dichlorobenzene for 90 min at 20 degrees C. They were fixed in ethanol-acetic acid solution (3:1) for 1 h, hydrolysed in 1N HCl, at 60 degrees C for 10 min, stained with Schiff's reagent for 1 h and squashed in 1% aceto-orceine stain. Storage of stained root tips in distilled water in refrigerator improved the quality of preparations. Secondly, La Cour's technique - maceration in a mixture of ten parts 1% aceto-orceine stain and one part 1N HCl, staining in 1% aceto-orceine also gave good results and could be useful because of its simple procedure. In order to establish the number of seeds with different ploidy level, 14 diploid and 36 triploid varieties of sugar beet were tested. It was found that 3 and 2 diploid varieties had less than 5 % and 10-13 % of seeds with triploid chromosome number, respectively. Admixtures of diploid seeds in the range of 10-14 %, 2-6 % and 1 % were found in 8, 19 and 8 triploid varieties, respectively. Only one triploid variety has 5 % diploid and 2 % of tetraploid seeds.
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