ASPECTS OF IN VITRO MICROTUBERIZATION, ON MEDIA WITH DAMINOZIDE, IN POTATO LOCAL VARIETIES (SOLANUM TUBEROSUM L.), FROM THE SUCEAVA GENE BANK COLLECTION

Abstract

The "in vitro" reactivity of the potato is, in general, very good, but that of the local genotypes can be quite varied, in terms of the growth speed, the size of the leaflets, the vigour of the plantlets or the microtuberization. The potato varieties from the "in vitro" collection are subcultured, periodically, on different micromultiplication media, constituting sources of biological material that will be passed into conservation media, or in different experiments of revitalization, or inducement of microtuberization. Daminozide (N-dimethylaminosuccinamic acid, B9, Alar) is a systemic growth regulator originally registered in the United States, in 1963, for use on ornamental plants, respectively on potted chrysanthemums. Its degree of harmfulness is very low, being classified in Category IV of toxicity, but it must be handled with care, as some studies consider it to have a carcinogenic effect if ingested. For the potato "in vitro" culture, it can be used in all stages, except the meristem inoculation, having a stimulating effect on the growth of the leaf surface and microtuberization, at concentrations of 6 -15 mg/litter of medium. Another result of the action of daminozide is the reduction of the length of the internodes, at concentrations of 20 - 30 mg/litter of medium, allowing a slow growth, at 6 – 100C, the extension of the duration between two subcultures, a preservation of 2 - 3 years, for the genotypes in the collection and stimulation of microtuber growth.