Fruit growing
and viticulture of South Russia

Annotation

In the process of wine production, the yeast is subjected to various stresses. This is a heat treatment during typing or the need to inactivate microflora, and the effect of low temperatures on wine processing for the prevention and elimination of dimness. If the yeast in the process of functioning are exposed to undergo similar stresses and their fermenting activity decreases. Of great interest is the study of resistance to technological stresses of new yeast strains isolated from the spontaneous microflora of grapes growing in various regions of the Krasnodar Territory. The aim of the work is to evaluate the resistance of new strains of wine yeast to the action of ethanol, sulfur dioxide, high and low temperatures. New strains of yeast isolated from spontaneous microflora of grapes were used as the object of study. As the control variant the known yeast races were selected. The stability of new yeast strains to sulfur dioxide was determined by the number of dead cells in the medium under study with various mass concentrations. The results obtained showed that the most of the strains tested are resistant to the presence of sulfur dioxide in the medium with a concentra-tion up to 200 mg/ dm3. It was found that the most of the new yeast strains of retained the ferment ability even at minus 6 ºC. It is shown that the most of new yeast strains studied have shown the greatest activity in the temperature range from 20 to 37.5 ºC. The study carried out confirm the expediency of using the new strains of wine yeast in the production of white table wines. Their technological characteristics are not worse and even superior to the known yeast races, including imported ones.

Annotation

The intensive production of fruits, directed on obtaining of stable and high-quality crops, causes the necessity to increase the resistance of cultivars to diseases. Under the modern conditions of rapid climat change, caused by anthropogenic, including agricultural environmental contamination, the protective and adaptive characteristics of the plants are reducing, and this factor determines the need to obtain the varieties of fruit crops adapted to a wide range of changing external conditions both abiotic and biotic. The article presents the data of early apple seedling selection for resistance to the two apple-tree dominant fungal infections: to scab under artificial infestation and to powdery mildew on a natural background. The object of research is the hybrid apple seedlings resulting from deliberate crossbreeding of K15461 sample of MOSVIR collection, that is relatively steady to both pathogens, with the susceptible Fuji cultivar. In 36% of the samples a scab lesions were not identified, 39% of the seedlings are resistant to a powdery mildew, according to the two years of the evaluation. 3 seedlings showed the resistance to the two pathogens, their share is 11 %. The evaluation of the plant also on complex features "cultivation" made it possible to identify the most of them as significant for breeding. The obtained results indicate a high prospect of using of K15461, as well as hybrid plants obtained in the combination of crossing of K15461 × Fuji, as donors of resistance to scab and powdery mildew. The hybrid seedlings can be used for study directed to the identification and mapping of new genes for resistance of apple plants to these pathogens.

Annotation

With the climate change on the planet towards warming, the fungi of the genus Alternaria Nees became more active. Due to the prevailing climatic conditions, some species of this genus changed their status and acquired signs of facultative parasitism and complete parasitism on a number of cultivated plants, including the apple-tree. In vitro scientific studies are required to effectively control the disease, in the pathogenesis of which a large number of species are involved. At the same time, it is necessary to achieve fast and guaranteed growth of each of the fungus in the experiments. In this regard, the selection for fungi of the genus Alternaria, causative agents of apple fruits core rot, optimal for the cultivation of nutrient mediums is urgent. The studies were carried out by methods of laboratory and comparative analyzes. The growth of two strains of the causative agent of the apple fruit core rot of Alternaria alternata (Fr.) Keissl. on 12 nutrient mediums. Colony growth rate and morphological and cultural traits were assessed. As a result of research the strains of apple fruit core rot agent, a variation not only in the growth rate of colonies, but also in their cultural characteristics, depending on the compositions nutrient medium. A comparative study of the morphological and cultural characteristics of A. alternata strains FR20IV and FR20VI on various nutrient mediums made it possible to identify three universal mediums most suitable for their cultivation and identification, namely carrot, potato agars and Sabouraud's medium, according to the following criterions: ensuring the maximum degree of sporulation, rapid growth and development of the mycelium of the fungus, as well as easiness of preparation of revealed optimum cultural mediums.

Annotation

A method for assessing the virulence of the apple scab pathogen on unripe fruits is offered in the paper. The necessary conditions for its effective implementation were determined experimentally. It is shown that unripe fruits should be selected from the genotypes of apple-trees, which are controlled by chemical preparations for fungal diseases, in the "walnut" development phase. Surface disinfection of fruits is not effective if they are infected with rot agents in the garden, which may prevent of further analysis. The same conditions for the preparation and selection of unripe fruits should be observed when they are further stored for deferred experiments. The method was tested on 9 monospore isolates of Venturia inaequalis isolated from the apple variety of Renet Simirenko. The manifestation of symptoms of scab lesions was characterized by the development of diffuse spots of dark olive or dark gray color with mainly superficial development of pathogen mycelium. The studied isolates of V. inaequalis characterized by different levels of virulence and aggressiveness on different genotypes of the host plant, reflecting the high heterogeneity of the pathogen population. Pathogenicity of most isolates was higher for immature fruits from the variety Renet Simirenko, showing their adaptability to the variety from which they were isolated. Slightly lower virulence and aggressiveness of isolates was observed for the Idared apple variety. Only one of the 9 isolates of the scab pathogen was virulent to the species of Malus x purpurea var pendula ornamental apple. The study carried out showed the effectiveness of the proposed method, under the conditions of fruit selection, in assessing the virulence and pathogenicity of monospore isolates of the apple scab pathogen in laboratory conditions.

Annotation

Over the past 15 years, the prevalence of pathogens of the genus Fusarium has increased in the gardens of the Krasnodar region, which are found both in the root rot pathocomplex and in the apple core rot pathocomplex. At present, much attention is paid to the biological method of plant protection, one of the directions of which is the use of microbiological drugs. In this connection, we studied the antifungal activity of microbiological preparations Rizoplan, Liq., Alirin B, WP, Fitosporin-M, P, Vitaplan, WP, registered on an apple tree to control scab, powdery mildew, moniliosis, as well as promising in relation to pathogens of rot roots and cores of apple fruits from the genus Fusarium � Trichocin, WP and Biocomposite, Liq. As a result of the study of the antifungal activity of microbiological drugs against fungi of the genus Fusarium, causative agents of rot of roots and fruits of the apple tree, both weak and very strong mycoparasitism were noted, but in most variants of the experiment, competition for the area of nutrition prevailed. Under the influence of some drugs, the shape, edge and color of the fungus colony changed. In general, for the entire sample of pathogens, the best bioagents were the antagonists of the drug Trichocin, WP, which suppressed all five strains with BE 50-90 % and showed hyperparasitism in one strain, as well as the drug Alirin B, Liq, which inhibited the growth of three strains with BE 56 -85 %, showing antibiosis or fungistatic antibiotic antagonism with the formation of a �sterile� zone.