Thaumatin II protein from the West African plant Thaumatococcus daniellii Benth. has unique properties – it is 3000 times sweeter than sucrose and is extremely resistant to heating in an acidic environment. It has been comprehensively studied and approved for use as a food additive E957. Thaumatin II belongs to the family 5 pathogenesis-related proteins and is involved in plant defense against fungal pathogens. The complex properties of thaumatin make it a promising object for use in breeding to improve the fruit and berry plants resistance to fungal pathogens, and to improve the taste of their fruits. A topical task is also to obtain plants producing recombinant thaumatin II for the needs of the food industry. The review examines the structure and properties of thaumatin II, the principles of its sweet taste formation, successes in obtaining plants transformed with the thaumatin II gene, and the results of their study. The prospects for using thaumatin II in further studies to improve the agronomic and consumer characteristics of agricultural plants, including fruits and berries, are discussed. The review is addressed to a wide range of readers, including researchers and breeders interested in modern molecular biological approaches for use in the selection of fruit and berry plants.

The paper presents results of the study into the correlation between the weather conditions and weight as well as biochemical properties of berries from 20 selected cultivars of black currant (Ribes nigrum L.) bred in the Lupin Russian Research Institute. The content of vitamin C, total sugars, organic acids, and berry weight were measured in the laboratory of the Horticulture Department, the Lupin Russian Research Institute. Standard study methodologies involved measuring vitamin C content in the berries by iodometric method (titration with 0.001N potassium iodate in the presence of a 1 % potassium iodide solution); assessing total sugar by Bertrand method as per GOST 13192-73; estimating the total acidity by titration of the aqueous extract with 0.1N alkaline solution in accordance with GOST 25555.5-82. The diversity of weather conditions during the study period allowed for identifi cation of the most favorable year for berry weight gain and the accumulation of biochemical properties. The year 2021 proved to be the most advantageous for berry weight gain. Throughout the years of study, the average berry weight ranged from 1.7 to 2.8 grams. The genotypes 8-3-155, 8-3-176, and 8-3-137 appear to be the largest fruit-bearing forms with weights ranging from 2.6 to 2.8 grams, exhibiting a high level of homeostasis (V<10 %). Correlation analysis revealed a strong positive dependence of berry weight on total precipitation (r = 0.99) and a weak positive correlation with the sum of active temperatures (r = 0.21). The accumulation of vitamin C in the selected forms ranged from 96 to 208 mg/100 g. The most vitamin-rich forms, exhibiting low variability over the years (V<10 %), included 8-3-14 (195 mg/100 g), 7-2-157 (205 mg/100 g), and 7-19-100 (208 mg/100 g). A strong negative correlation (r=-0.98) was found between the sum of active temperatures and the accumulation of vitamin C in the berries. A higher accumulation of sugars was observed in 2022. Throughout the study period, this indicator varied from 5.7 % to 8.5 %. Selection numbers 6-15-65 (8.2 %), 8-3-171 (8.2 %), 8-3-129 (8.3 %), and 8-3-113 (8.5 %) were marked with high and stable sugar accumulation (V<10 %). A strong positive correlation was found between sugar accumulation and the sum of active air temperatures from May to July (r=0.99). The average acid content across the samples ranged from 1.4 % to 2.5 %. The genotypes 8-3-176, 8-3-110, 8-3-129, 8-3-113, 8-3-125, and 7-18-31 demonstrated consistent low acidity (from 1.4 % to 1.9 %). Correlation analysis revealed a strong positive relationship between total acidity and precipitation (r=0.99).

Black currant refers to polyvitaminic berry crops. Its berries contain key antioxidant components, namely ascorbic acid and phenolic compounds, including anthocyanins and catechins, characterized by high activity of rutin. The abundant presence of the two vitamins is particularly valuable, considering their synergistic eff ects. The present study is aimed at investigating 35 black currant varieties developed by the Russian Research Institute of Fruit Crop Breeding and included in its genetic resource collection. The study was conducted under the conditions of the Central Russian region (Orlovskaya Oblast), focusing on the antioxidant components in the berries (ascorbic acid, anthocyanins, catechins). The studied cultivars have been established as sources of biologically active compounds. A signifi cant range of variability has been noted for each component: from 81.8 mg/100 g (‘Arapka’) to 249.4 mg/100 g (‘Nadina’) for ascorbic acid; from 74.1 mg/100 g (‘Blakeston’) to 319.8 mg/100 g (‘Ershistaya’) for anthocyanins; and from 86.9 mg/100 g (‘Desertnaya Ogoltsovoy’) to 431.7 mg/100 g (‘Ekzotica’) for catechins. The coeffi cients of variation calculated for each cultivar indicate that the climatic conditions during the growing season have a greater impact on the accumulation of anthocyanins with high activity of rutin in blackcurrant berries than on ascorbic acid content. The analysis revealed varieties of crops with elevated or high levels for each indicator: 51.4 % of crops exhibit ascorbic acid content exceeding 150.0 mg/100 g; 54.3 % demonstrate anthocyanin levels above 150.0 mg/100 g; and 31.4 % contain catechins exceeding 250.0 mg/100 g. The following varieties were identifi ed as sources of antioxidant activity for breeding programs aimed at enhancing the chemical composition of crops: ‘Desertnaya Ogoltsovoy’, ‘Muravushka’, ‘Nadina’ – for ascorbic acid content (200.0 mg/100 g and above); ‘Arapka’, ‘Assol’, ‘Ershistaya’, ‘Zusha’, ‘Ladushka’, ‘Nadina’, ‘Nyura’, ‘Yubiley Orla’ – for anthocyanin content (over 200.0 mg/100 g); ‘Ariadna’, ‘Assol’, ‘Ershistaya’, ‘Zusha’, ‘Kipiana’, ‘Muravushka’, ‘Nadina’, ‘Nyura’, ‘Orlovia’, ‘Ekzotica’, and ‘Yubiley Orla’ – for catechin content (over 250.0 mg/100 g); ‘Zusha’, ‘Kipiana’, ‘Ladushka’, ‘Muravushka’, ‘Nadina’, ‘Chudnoye Mgnovenie’, and ‘Ekzotica’ – for biochemical traits.

The climate warming and destabilization are currently recognized as signifi cant factors aff ecting the development of viticulture worldwide. To mitigate the production risks of various agricultural crops, the prospects of less productive but more stable early varieties are being explored. Plant phenology serves as a sensitive indicator of climate changes. The study involves observations on the length of the productive period and phenological data of 30 grape varieties, obtained within 25 years or more from 1981 to 2022. The sample is diverse in terms of taxonomic affi  liation, cultivation methods, intended use, and ripening periods. The present study is aimed at comparing stability of the length of the productive period for 30 grape varieties from the Potapenko Donskaya Ampelographic Collection during the periods of 1981‒2001 and 2002-2022. The standard deviations of the length of the productive period were calculated in order to assess instability for each period. The Wilcoxon criterion revealed that, on average, the length of the productive period for 30 grape varieties from 2002 to 2022 decreased by 10 days compared to the period from 1981 to 2001 (from 139 to 129 days), while the standard deviation increased from 8.2 to 10.9 days. The most stable length of the productive period was observed for ultra-early, very early, medium, and medium-late varieties, whereas the least stable varieties included early and early-medium varieties which ripe between the third decade of August and the fi rst decade of September. The instability in the length of the productive period of early and early-medium varieties can be attributed to the sharply increased variability of August temperatures and the rise in the number of days with temperatures exceeding 35 °C, which produces hindering eff ect on the development of grapes. The impact of the high temperatures observed in July and August was mitigated by an extended duration of autumn periods with temperatures over 10 °C for the mid- and mid-late grape varieties. 

The paper presents the results of studies into the impact of agromeliorative practices conducive to mitigating the negative eff ects of drip irrigation with mineralized waters on the fertility of chernozem soils and the productivity of intensive apple orchards. The study is aimed at assessing the biological effi  ciency of agromeliorative practices designed to reduce the adverse eff ects of irrigating apple orchards with mineralized irrigation waters. The study objects included typical chernozems and intensively irrigated apple orchards on M9 rootstock in the steppe fruit-growing zone of Krasnodar Krai. The effi  ciency of practices aimed at leveling negative soil processes was established through the combined application of phosphogypsum at a rate of 5 t/ha and straw mulching at a thickness of 15 cm in the near-trunk areas of apple orchards. The study revealed a tendency to increase the content of mobile phosphorus compounds in the local soil moistening zone in experimental variants with the introduction of phosphogypsum. Mulching of the soil in the near-trunk areas resulted in improved potassium nutrition for apple trees, an increase in the content of mobile potassium compounds in the near-trunk area soil from 53 to 343 mg/kg and a growth in total potassium content in the leaves by 0.22 % dry matter compared to the control group. The combined use of phosphogypsum and straw mulch decreased the content of mobile potassium compounds by 26-79 mg/kg of soil. The nutrient content in the leaves of apple trees in all experimental variants revealed optimal and elevated levels with a noted reduction in sodium cation content in the leaves by 17.9-35.7 % when employing agromeliorative practices. The use of phosphogypsum alone in early spring improved calcium nutrition and signifi cantly increased fruit set of apple trees in the fi rst year of ameliorant application. Complex use of phosphogypsum and soil mulching led to a reliable growth in average fruit weight by 6.8–8.8 % and increased yield of apple trees from 4.2 to 7.5 t/ha. Furthermore, more prolonged dissolution of ameliorant under the mulching layer was noted, which promoted gradual water-soluble calcium intake into the soil. 

The results of agrochemical field experiments conducted in an orchard of columnar apple tree (Malus domestica Borkh.) in the Moscow Oblast during the period of 2021–2022 are presented. The research objects were the ‘Valuta’, ‘Triumph’, and ‘President’ varieties. The effect of foliar treatments of plants with Bacillus subtilis (strain V167) and Bacillus subtilis (strain V417) strains, as well as Bacillus subtilis – based microbiological preparations “Extrasol” (strain Ch13) and “Phytosporin-M” (strain 26D) on such indicators as the microbiological and chemical composition of leaves, the content of photosynthetic pigments in leaves, and chlorophyll fluorescence indices was studied. Plant samples were analyzed using standard methodology. When applying strains and microbiological preparations based on Bacillus subtilis, the taxonomic composition of endophytic bacterial forms cultured on dense nutrient media and isolated from leaves was represented by the Bacillus genus. For comparison, when treating plants with Bacillus subtilis strain V417 and “Phytosporin-M”, the Pseudomonas genus was also detected. The number of cultivated forms of endophytic bacteria in the treated plants was consistently growing, having reached the maximum value of 406800 CFU/g in the “Extrasol” variant. Notably, the content of photosynthetic pigments in leaves depended on both the plant variety and the strain used. High values of maximal efficiency of PSII photochemistry (F_v/F_m) were observed both in experimental and control variants. A consistent increase in leaf N content was detected when applying “Extrasol”. In this respect, the ‘President’ variety showed the greatest response, i.e., a 16.1 % increase compared to the control. The ‘President’ and ‘Triumph’ varieties demonstrated an increase in leaf K content under the influence of foliar treatment of plants with the studied strains and microbiological preparations. The greatest effect of 17.2 % above the control was observed in the ‘Triumph’ variety when treated with “Extrasol”. Foliar treatments of ‘President’ and ‘Valuta’ plants with microbiological preparations contributed to increased, compared to the control, Mg contents in their leaves.