Frankovka Research Articles

The effect of resistance of rootstocks to crown gall (Agrobacterium spp.) on the susceptibility of scions in grape vine cultivars

The effects of two grapevine rootstocks on susceptibility of grafted scions to crown gall (Agrobacterium vitis and Agrobacterium tumefaciens) was investigated in greenhouse and field experiments. The incidence of crown gall on a susceptible grape scion cultivar (Vitis vinifera, cv. Kiralyleanyka) was not affected by grafting it on a crown gall resistant rootstock (Vitis riparia, cv. Gloire) or on a susceptible rootstock (V. berlandieri × V. riparia, cv. Teleki 5C) when the inoculated vines were observed over a 2‐month period in the greenhouse. Weights of galls that were induced by six of eight strains of Agrobacterium (six A. vitis and two A. tumefaciens) were not significantly different, but A. tumefaciens strain 16/6 and A. vitis strain 2/3 produced significantly larger galls on Kiralyleanyka vines that were growing on their own roots or were grafted on 5C than on those grafted on Gloire. When the same vines were planted in the field and observed over a 4‐year period, no differences in incidence of crown gall were appa_rent until the third and fourth years, when vines grafted on Gloire had less crown gall than vines on 5C. By that time, the natural symptoms (galls along the trunk) of the disease appeared, coinciding with the decline of whole vines. In another field experiment, with naturally infected scions of V. vinifera, cv. Blau Frankisch (susceptible), crown gall was appa_rent on vines grafted on both rootstocks after 2 years, but in the fifth year 79% of the vines on 5C had crown gall whereas only 9% on Gloire showed symptoms. After the appearance of typical natural symptoms, vines showed reduced vigor with substantial loss of trunks and entire vines. During this period, many vines on 5C died as compared with only a few on Gloire. By the end of the sixth year, 13% of the originally planted vines on 5C and 82% on Gloire were alive, and although many pathogenic strains of Agrobacterium spp. were isolated from the roots of 5C, none was isolated from Gloire.

THE PHYSICOCHEMICAL CHARACTERISTICS OF RED WINES OBTAINED FROM BURGUND VARIETY FROM MINIS VINEYARD

SUMMARY The researches which were done regarded the evolution of physical and chemical factors for superior red wines from Burgund grapes variety obtained in Minis vineyard during five years period of time. Superior qualitative red wines from Burgund Mare variety obtained with maceration fermentation technology in metallic rotation tanks, by adding Vinozym G enzymatic mixture, after the alcoholic and malolactic fermentation, we re conditioned and stabilised. Wine maturation was made in oak wood cask and the obsolescence in glass bottles, assuring a content of 25-35 mg/l free SO 2. Physicochemical analyses were made for the wine which pass through this technology, after the alcoholic fermentation was finished at 3; 6; 9; 12; 18 months and after that yearly so the wine obtained without adding enzymatic mixtures and the wine obtained through maceration ‐ fermentation process, by adding Vinozym G enzymatic mixture. The alcohol content, the total acidity and volatile acidity wer e determined with an oeno‐chemical distillation equipment (D.E.E.) equipped with steam generator (VADE) in purpose to determine the volatile acidity. Analysing the obtained dates were observed that the total acidity of the wines treated with exogenous enzymatic mixtures, is higher comparative with the ones which weren’t enzymatic treated, but in both cases it is decreasi ng during the maturation and obsolescence period. The volatile acidity is smaller to enzymati c treated wines comparative with the ones which weren’t enzymatic treated and in both cases t he maturation and obsolescence period of time is increasing. The alcohol content of wines ob tained by Burgund grapes variety from Minis vineyard during the studied period of time is varying between 11,70 % vol. and 12,20 % vol. The alcohol quantity to wines which was enzymatic treated is 0,1-0,2 % vol. bigger comparative with the one which was not enzymatic treated. During the maturation and obsolescence period the alcohol quantity is decreas ing by 0,2-0,3 % vol. in average. BIBLIOGRAPHY