The effect of sorbitol and conservation period on the in vitro evolution of Solanum tuberosum L. plantlets

Abstract

Local potato varieties are kept at Suceava Genebank, Romania, in the experimental field collection and in vitro by slow growth method which allows limited plantlets growth, thus prolonging the time between two subcultures. The paper presents some results concerning the influence of a growth inhibitor, namely sorbitol (as osmotic agent), in the development of plantlets belonging to five local varieties of potato (Solanum tuberosum L.), after different periods of in vitro storage, while reducing temperature and light intensity. During the experiment were evaluated several morphological aspects: number, length and branching of shoots, roots, number of viable nodes and number of viable shoots. The observations revealed that there has been registered a growth retardation of inoculums, while maintaining their viability and vitality. Although there were differences in growth patterns of these five potato varieties, as a general rule, the main effects of growing conditions has been a reduced plantlets height (2-4 cm) by the shortening of internodes and the contraction of leaflets size, to 1.5-2 mm. The results obtained during in vitro conservation for 17 months, of five local potato varieties on MS medium with 40 g/l sorbitol (C24 culture media), recommend this solution for a wider use in the preservation of potato collection from the Suceava Genebank.