Zvjezdana Marković

Cryopreservation of grapevine ( Vitis vinifera L.) in vitro shoot tips

In this work, we compared the efficiency of encapsulation-dehydration and droplet-vitrification techniques for cryopreserving grapevine (Vitis vinifera L.) cv. Portan shoot tips. Recovery of cryopreserved samples was achieved with both techniques; however, droplet-vitrification, which was used for the first time with grapevine shoot tips, produced higher regrowth. With encapsulationdehydration, encapsulated shoot tips were precultured in liquid medium with progressively increasing sucrose concentrations over a 2-day period (12 h in medium with 0.25, 0.5, 0.75 and 1.0 M sucrose), then dehydrated to 22.28% moisture content (fresh weight). After liquid nitrogen exposure 37.1% regrowth was achieved using 1 mm-long shoot tips and only 16.0% with 2 mm-long shoot tips. With droplet-vitrification, 50% regrowth was obtained following treatment of shoot tips with a loading solution containing 2 M glycerol + 0.4 M sucrose for 20 min, dehydration with half-strength PVS2 vitrification solution (30% (w/v) glycerol, 15% (w/v) ethylene glycol, 15% dimethylsulfoxide and 0.4 M sucrose in basal medium) at room temperature, then with full strength PVS2 solution at 0°C for 50 min before direct immersion in liquid nitrogen. No regrowth was achieved after cryopreservation when shoot tips were dehydrated with PVS3 vitrification solution (50% (w/v) glycerol and 50% (w/v) sucrose in basal medium).

Cryopreservation of grapevine (Vitis spp.)—a review

Grapevine (Vitis genus) is one of the economically most important fruits worldwide. Some species and cultivars are rare and have only a few vines, but represent national heritages with a strong need for preservation. Field collections are labor intensive, and expensive to maintain, and are exposed to natural disasters. In addition, infection with pathogens, especially viruses, is common in grapevine because of vegetative propagation, which is conventionally used for this genus. Cryopreservation provides an alternative and ideal means for the long-term preservation of Vitis germplasm, which can be used as a backup to field collections for important autochthonous cultivars or only as cryo-banks for rare, native cultivars that are worthy of preservation. Cryotherapy, based on cryopreservation protocols, provides an efficient method for the eradication of grapevine viruses. This review provides comprehensive and updated information on cryopreservation for long-term preservation of genetic resources and cryotherapy for virus eradication in Vitis. Additional research in grapevine cryopreservation and cryotherapy is needed.

In vitro introduction of healthy and virus-infected genotypes of native Croatian grapevine cultivars

We evaluated the response of eight economically important Croatian grapevine cultivars and studied the impact of their sanitary status on in vitro introduction, by comparing the response of healthy and virus-infected genotypes of one cultivar. Nodal explant survival on three media, M1 (half-strength MS), M2 (full-strength MS) or M3 (full-strength MS with 4.4 µM L−1 benzylaminopurine) was measured after 2 weeks and regrowth after 8 weeks. After 8 weeks, average shoot length and node number were significantly higher on M2 compared to M1 and M3. M3 induced significantly shorter average internode length, compared to M1 and M2. Survival of one healthy and of five cultivar Plavac mali genotypes infected with GFLV, GLRaV-1, GLRaV-3, GLRaV-3+GVA and GLRaV-1+GLRaV-3 was 97.5 and 82.8–87.5%, respectively. Regrowth of the healthy genotype reached 95.5%, but dropped to 5.5–31.4% in infected ones. The healthy genotype showed significantly higher shoot length (6.3 cm) and node number (7.3) compared to infected genotypes, with shoot length between 1.2–2.6 cm and node number between 1.2–3.0. By contrast, internode length was not significantly different between the healthy and the infected genotypes. The present work represents the first successful in vitro introduction for three of the eight native Croatian cultivars studied.

Intravarietal agronomic variability in croatian native "Vitis vinifera" L. Cultivar Grk with female flower and seedless berries

The Croatian native, Vitis vinifera L. cv. Grk, is one of only a few wine cultivars with a female flower, resulting in two types of berries in the cluster: fully developed seeded (~3.5 g) and undersized seedless (~0.7 g), both ripe at harvest. This study investigated the intravarietal variability of Grk and the impact of the different proportion of seedless berries on grape yield and quality of Grk clones. Significant differences in cluster proportions of seedless berries among Grk clone candidates were determined. A high positive correlation was found between the seedless berry proportion and single berry weight, must tartaric acid content, and free volatile terpenes. These results indicate that it is possible to select clones with a higher proportion of seedless berries, which can then be used to improve the wine quality of Grk.

Polyphenolic Composition of the Berry Skin of Six Fungus-Resistant Red Grapevine Varieties

Phenolic compound profiles were investigated by high-performance liquid chromatography-diode array detector in three vintages to assess genotypic variation in berry skins of six resistant grapevine varieties: “Cabernet Cortis,” “Chancellor,” “Léon Millot,” “Maréchal Foch,” “Monarch,” and “Regent.” The research has revealed a significant difference among the varieties in the total phenolic content, anthocyanins, flavanols, and flavan-3-ols. A clear differentiation of all varieties by means of the polyphenol profile using discriminant analyses has been achieved. “Regent” reached the significantly highest total polyphenol content, as well as total anthocyanin and total flavonol content. The polyphenol profile of “Chancellor” was quite different from all of the other studied varieties. Although being closely related, “Maréchal Foch” and “Léon Millot” showed qualitatively and quantitatively quite different polyphenol contents. No clear connection between the genetic origin of the varieties and their polyphenol profiles has been found.