Abstract:
This study was performed to
reveal the changes in cell division, as a
result of the prolonged period of subculture
on micropropagation medium, of five local
varieties of Solanum tuberosum L.
maintained on in vitro collection at Suceava
Genebank, Romania. For this purpose it was
used the Murashige-Skoog medium (MS-
1962) with addition of 40 g/l sucrose, and 6
mg/l daminozide. The effect of prolonged
period of subculture up to two and 12
months was expressed as mitotic index and
frequency of cells with abnormal division.
Mitotic index ranged from 20.1 to 22.1%
after 12 days, between 15.5 - 17.7% after
two months and between 17.7 - 19.2% after
12 months of subculture. The results
obtained showed that the frequency of
aberrant cells increased with the
preservation time on the in vitro cultures
and their accumulation rate depended on the
genotype. Were identified interphases with
micronuclei, metaphases with retarded
chromosomes, ana-telophases with
chromosomal bridges, retarded
chromosomes and chromosomal fragments,
but their percentage was low in all the
genotypes.
