In vitro tissue culture, a tool for long-term conservation of Croatian grapevine genetic resources

In vitro culture obtain the tools to perform specific studies that it would be impossible to carry out with the whole plants grown on field or under greeenhouse conditions. Cryopreservation presents the long-term conservation without a metabolic changes of plant material and cryotherapy can be efficient in virus elimination. Tested cryopreservation protocols did not gave sufficient regeneration. Preculture media of cryopreservation profotocols was evaluated with Croatian grapevine cultivars (ꞌGraševinaꞌ, ꞌPlavac maliꞌ and ꞌPošipꞌ) with different antioxidants (salicylic acid, ascorbic acid and glutathione). The highest growth in vitro was achieved on the medium with the addition of glutathione and the lowest on the medium with addition of salicylic acid. The growth in vitro and regeneration after cryopreservation was depended on genotype and sanitary status. A reliable protocol for the regeneration after cryopreservation (within cryotherapy) should be defined for each grapevine cultivar. Virus elimination was tested by meristem tip culture with 18 Croatian cultivars, whereas, regeneration in vitro was between 6.82 and 53.22%, but virus elimination was achieved only with three cultivars and was very low (23.8%). Additionally, the method of conservation of grapevine cultivars by cultivation in isolated conditions of small glass containers (2L), was tested. Two cultivars were grown in containers in the growth chamber under controlled conditions. This study has revealed that the plants can be conserved this way for more than 2 years (ongoing trial). Plants grown this way can be the source of plant material for new in vitro introduction and multiplication. Overall, the presented methods should be further evaluated for broad application.