New source material for improving raspberry assortment in the Central region of Russia

The aim of the research is to search new sources of the main economically valuable traits for further breeding of raspberry. Nineteen previously created selected forms were studied for winter resistance components under controlled conditions, for resistance to major fungal diseases, productivity components, strength and biochemical composition of fruits. The zoned Gusar variety was used as the control. The work was carried out in 2018-2020 according to generally accepted techniques. Artificial freezing of raspberry stems was carried out in the climate chamber TH-6 JEIO TECH. According to the results of the studies, selected forms 8-10х-1, 6-125-4, which have an increased resistance to certain components of winter resistance, have been identified. Hybrids 2-115-1 and 1-188-1 have cumulative resistance to winter damage factors. Based on the integrated resistance of raspberry hybrids to the main fungal diseases, new sources have been revealed: forms 1-124-1, 2-115-1, 2-115-2, 1-111-21, 1-8-2, 2-35-1, 2-90-3, 6-125-4, 3-4-2, 8-10х-1, 4-33-21 and 4-122-2. The degree of their damage did not have a significant influence on winter hardiness, productivity and quality of berries. As the result of study of components of the raspberry productivity, selected forms (1-111-21, 2-90-2 and 2-90-3), forming fruits with an average weight of more than 4.0 g, and genotypes with large and one-dimensional fruits (1-176-21, 2-35-1, 4-33-21, 1-124-1) not growing smaller from picking to picking were identified. The highest potential productivity was noted for selections 2-115-1, 1-111-21, 1-188-1, 4-46-2, 2-90-2 and 2-90-3, capable to form a yield of more than 1.3 kg per bush. The selections 1-124-1, 2-90-2 and 2-90-3 are distinguished by an increased strength of the fruits. They form fruits with a crushing force exceeding 5.0 N, which ensures the safety of integrity and transportability when manually harvested. No complex sources of increased accumulation of biologically active substances have been identified. Genotypes with a high content of individual biochemical substances were selected. The highest accumulation of soluble solids and sugars was noted in the samples 2-90-3, 18-11-4 and 2-115-1. Highest accumulation o the vitamin C was observed in the samples 6-125-4 (59.8 mg/100 g) and 2-90-3 (61.5 mg/100 g). As new sources in breeding to improve the taste characteristics of raspberry, it is necessary to use selected forms 2-90-2, 2-115-1 and 6-125-4, approaching in taste to the standard variety Novost Kuzmina. Selected forms 2-90-2, 2-90-3 and 2-115-1 are new sources in raspberry breeding, combining a complex of economically valuable traits at a high level.

THE INFLUENCE OF ROOTSTOCK ON THE FROST RESISTANCE OF SWEET CHERRIES DURING THE THAW

Studies on the frost resistance of sweet cherries were carried out in 2019–2020 in the FSBSI of the Federal Horticultural Research Center for Breeding, Agrotechnology and Nursery in laboratory conditions by artificial freezing in the climate chamber TH-6 JEIO TECH-1000. Objects of research: Tyutchevka and Chermashnaya varieties grafted on 8 clonal rootstocks (Colt, Izmailovsky, AVCH-2, V-5-88, VC-13, Moskoviya, VSL-2, Stepnoy Rodnik). The aim of the research is to study the effect of clonal rootstocks on the frost resistance of cherry buds and tissues during the thaw and to identify the most frost-resistant scion-rootstock combinations for the 3rd component. It was found that after freezing at t = -20 °C during the thaw, the safety of flower buds in the Tyutchevka variety in both years of research was more than 80 %, and in the Chermashnaya variety — from 20 to 30 %, depending on the year. The limits of changes in the frost resistance of generative buds of varieties depending on the rootstock are shown: in the Tyutchevka variety — from 66.8 % (V-5-88) to 96.4 % (Izmailovsky), and in the Chermashnaya variety — from 7.7 % (V-5-88) to 65.5 % (AVCH-2). When using the AVCH-2 and Izmailovsky clonal rootstocks, the safety of flower buds increased by 30 % compared to the Colt rootstock. The most frost-resistant scion –rootstock combinations for each variety were identified: Tyutchevka/Izmailovsky and Tyutchevka/Stepnoy Rodnik, which preserved more than 90 % of the living rudiments; Chermashnaya/AVCH-2 (65.5 %) and Chermashnaya/Izmailovsky (40.1 %). Vegetative buds and tissues of annual branches were practically free of freezing in the studied varieties when grafted on the rootstocks of Stepnoy Rodnik and AVCH-2. In the Chermashnaya variety, damage of about 1 point of the phloem and vascular bundle under the buds was noted when grafting on rootstocks V-5-88 and Colt.

Analysis of Temperature Anomalies during Thermal Monitoring of Frozen Wall Formation

The paper describes a distributed temperature sensing system that was used to monitor the artificial freezing of soils during the construction of a potash mine shaft. The technique of reconstructing the temperature field by solving the inverse problem in the entire volume of frozen soils using the measured temperatures in four thermal monitoring (TM) wells is described. Two local anomalies in temperature distributions in TM wells are described and analyzed theoretically using thermo-hydraulic modeling. The first anomaly concerns the asymmetric temperature distribution in one of the soil layers and is associated with the influence of natural groundwater flow in the horizontal direction. The second anomaly consists of a sharp decrease in water temperature in the section of the TM well located inside the freezing contour. Calculations showed that it is most likely associated with the entry of cold groundwater from the overlying layers of soils through a well filter at a depth of 160 m and the subsequent movement of the water up the well.

Methods for Measuring Frost Tolerance of Conifers: A Systematic Map

Frost tolerance is the ability of plants to withstand freezing temperatures without unrecoverable damage. Measuring frost tolerance involves various steps, each of which will vary depending on the objectives of the study. This systematic map takes an overall view of the literature that uses frost tolerance measuring techniques in gymnosperms, focusing mainly on conifers. Many different techniques have been used for testing, and there has been little change in methodology since 2000. The gold standard remains the field observation study, which, due to its cost, is frequently substituted by other techniques. Closed enclosure freezing tests (all non-field freezing tests) are done using various types of equipment for inducing artificial freezing. An examination of the literature indicates that several factors have to be controlled in order to measure frost tolerance in a manner similar to observation in a field study. Equipment that allows controlling the freezing rate, frost exposure time and thawing rate would obtain results closer to field studies. Other important factors in study design are the number of test temperatures used, the range of temperatures selected and the decrements between the temperatures, which should be selected based on expected frost tolerance of the tissue and species.

Resistance of generative organs of sweet cherry to spring frosts after artificial freezing

Aim. The purpose of this research was to study the sustainability of Institute bred sweet cherry cultivars to spring frosts during flowering by the method of artificial freezing and to identify resistant cultivars.Material and Methods. Seven Institute bred sweet cherry cultivars were studied: 'Adelina', "Malysh", "Orlovskaya Rozovaya", "Orlovskaya Feya", "Podarok Orlu", "Siyana" and "Trosnyanskaya". Spring frosts were simulated in an "Espec" PSL-2KPH climate chamber in early May at -1°, -2°, -3° and -4°C. At each temperature regime, 100 pcs of flowers and buds of each cultivar were taken in 3-fold repetition. Temperature was lowered at the rate of 1°C per hour. The duration of exposure to negative temperatures was 3 hours.Results. Damage to the stamens and pistils was assessed by the darkening of the tissues. In buds and blooming flowers after frosts, the pistils were first damaged but the stamens were not. Resistance to spring frosts decreased with the phenological development of the cherry's generative organs. The beginning of damage to the flowers as a result of the artificial freezing was noted at a temperature of -1°C. At the same time, the high stability of cherry buds was noted. Modeling frosts of -2°...-4°C increased the number of dead flowers and buds. The resistance of sweet cherries to spring frosts was found to depend on the genotype and stage of development of reproductive organs. A different sum of active temperatures for the beginning of flowering and ovary formation was noted, indicating the onset of phenological phases in which generative organs are susceptible to spring frosts.Conclusion. The experiment made it possible to distinguish a medium-resistant cultivar "Malysh" which was resistant to spring frosts. Weakly stable genotypes were "Orlovskaya Rozovaya", "Orlovskaya Feya", "Trosnyanskaya" and "Siyana". Unstable cultivars were "Adelina", and "Podarok Orlu". During the formation of the ovary, the greatest potential for resistance to spring frosts was shown by "Podarok Orlu".

Freezing Method for Rock Cross-Cut Coal Uncovering: Aging Characteristic of Effective Freezing Distance on Injecting Liquid Nitrogen into Coal Seam

Based on artificial freezing engineering practice, the comprehensive technology is suggested to realize safe and fast rock cross-cut coal uncovering, which mainly includes four steps of drilling, water injection wetting coal, gas drainage, and injection liquid nitrogen into coal seam. Freezing test of liquid nitrogen injection into coal is carried out to obtain the cooling curves, and comparing the test results, the numerical inverse method is applied to determine the thermal conductivity of coal seam. Then, the model of injecting liquid nitrogen into coal seam is established to simulate and analyze the aging characteristic of effective freezing radius. The results show that the thermal conductivity of wetting coal increases linearly with temperature decreasing. The periodic method with 8h intervals can be adopted to inject liquid nitrogen into coal seam, and the freezing wall is formed around the injection hole. With the increase of freezing time, the effective freezing radius (below 273.15 K) increases by power exponent, and the freezing speed in coal seam decreases gradually. This result will provide a theoretical basis for layout optimization of injection holes in rock cross-cut coal uncovering.

Physical Model Test of Artificial Freezing-Inclined Shaft

Based on the vertical straight artificial freezing engineering in Northern Shaanxi, a three-dimensional (3D) physical simulation test system was developed, consisting of six parts, which are simulation box, shaft model, loading system, freezing system, external environment simulation system, and data acquisition system. The physical model and actual test results show that the 3D physical simulation test system is reasonable and reliable. The test model results show that the distance from the freezing pipe significantly affects the freezing wall temperature. For the case of four adjacent, two adjacent tangential freezing, and two adjacent axial freezing pipes, the cooling rates were 1.37, 2.79, and 1.96°C/h, respectively. The field measurement showed that the proximity to the freezing pipe increases the cooling rates. The cooling rates of points 1k#, 2k#, and 3k# were 25.61, 25.32, and 25.35 mm/d, respectively. The increment rates of vertical and horizontal freezing pressures with temperature were 8.78 and 2.97 kPa/°C, respectively. Furthermore, the freezing pressure time fitting formula was given. The calculated results of temperature and freezing pressure are consistent with the measured results, indicating the reasonability and reliability of the 3D physical simulation test scheme of the artificial freezing-inclined shaft in this work.