The dynamics of cell division in some local potato varieties cultivated in vitro on micropropagation medium

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.