Stone Fruit Crops Research Articles

Фенологические особенности развития сортов вишни в меняющихся погодно-климатических условиях

Annotation. Cherry is a stone fruit crop cultivated in almost all regions of Russia. Currently, there is a significant change in weather and climatic conditions, their impact leads to a shift in the phenological phases of plant development and to disruption of the stages of organogenesis. In this regard, there is a need to study the passage of phenological phases of cherry development in the changing weather and climatic conditions of the southern region. The research was carried out on the basis of the collective use center (CUC) “Genetic collection of fruit crops” in the period 2020-2023 in the Kuban horticulture zone of Krasnodar region. The objects of research were 11 varieties of sour cherries of various ecological and geographical origins. Planting scheme is 5x3 m, rootstock is antipka seedlings. During the research, the sum of active temperatures during the cherry growing season was determined, which determines the occurrence of the main phenological phases of development of cherry varieties in the annual development cycle. It was established that over the years of research, on average, the sum of active temperatures exceeded the long-term average by 551,7 °C. It was determined that during the research period the phenological phase “beginning of growing season” of cherries took place at a sum of temperatures of 32.8-54.2 °C. The phenological phase of “beginning of flowering” for most varieties in 2020 and 2023 occurred earlier than the long-term average date by 2-8 days, in 2023 – by 2-6 days, and in 2021-2022 – later by 2-14 days. It was revealed that at the phenophase "beginning of flowering", early cherry varieties (Krasnodarskaya sladkaya, Chudo vishnya), medium (Timati, Feya, Assol’, Svatlaya) are strongly affected by stress. Tamaris and Hodosa cherry varieties of late ripening showed relatively high resistance to stress during the flowering period. Key words: cherry, variety, phenological characteristics, flowering, climate.

Biochemical characteristics of some varieties of peach and nectarine grown in Sochi

Biochemical characteristics and features of the most promising varieties of stone fruit crops (peach, nectarine) submitted for research have been shown. Biochemical analyzes of peach and nectarine fruits grown in the humid subtropics of Russia were carried out in 2019-2020 at the Subtropical Scientific Center of the Russian Academy of Sciences in the Laboratory of Plant physiology and Biochemistry. The following varieties were used for biochemical analyzes: Rannyaya zarya, Larisa (control one), Osenniy rymyanets, Anton Chekhov, Big Top, Nectarine Sklor. The content of biologically valuable substances in stone fruits, which determine not only their taste characteristics, but also their nutritional and therapeutic and prophylactic effects, is a criterion for high commercial quality of products. That is why we are faced with the task of assessing the chemical composition of peaches and nectarines, which directly depends on weather and climate conditions, varietal characteristics, place of growth, etc. It is known that the pulp of peaches and nectarines contains a large amount of sugars, organic acids (mainly malic), vitamins, enzymes, macro- and microelements. In assessing the taste qualities of peaches and nectarines, the content of sugars, acids and vitamin C (or ascorbic acid), which acts as an antioxidant, is of great importance. Biochemical analysis of peach and nectarine fruits revealed the maximum sugar content - 10.16% in the Larisa variety (control one) of mid-late ripening period, the minimum in the Rannyaya Zarya variety of early ripening period, which is significantly lower by 1.3 times compared to the control one. High vitamin C content in the Larisa variety fruits was noted - up to 16.56 mg%, which is significantly higher than other studied varieties by 2.60-5.19 mg%. Promising varieties Larisa and Anton Chekhov were distinguished by a balanced taste of fruits and resistance to abiotic factors of the environment of the Black Sea coast of Russia.

Genetic resources of the genus Prunus L. and their role in stone fruit breeding

Stone fruits such as apricot, cherry plum, cherry, peach, plum, and sweet cherry are highly popular in the Russian Federation. They are cultivated in the industrial gardens of large agricultural producers, as well as the plantings on farms and household plots. The fruits of these species can be consumed fresh for a considerable period of time. The application of some processing methods (cooling, freezing, and storage in a special atmosphere) significantly extends this period. Stone fruits are also suitable for producing a wide variety of processed products. The biochemical composition of fruits determines their high energy value and dietary properties. The representatives of the genus Prunus L. exhibit great genetic diversity. Due to their high polymorphy, they cover a large area. In regions with favorable weather and climatic growth conditions, stone fruits constitute the main industrial varieties. High requirements for industrial varieties determine the relevance of breeding improvement of available varieties. Representatives of the genus Prunus are characterized by a long juvenile period, different ploidy of species, high incompatibility, as well as heterozygosity for a large number of traits with a comparatively small number of identified genes. This fact significantly complicates genetic studies. The assortment of stone fruit crops in central Russia was renewed in several main directions. Most varieties were created through intervarietal crosses within a species. The current breeding work is aimed at creating new stone fruit species, as well as at improving the existing assortment. Along with the crossing of geographically distant varieties within a species, distant hybridization is one of the promising directions. In this way, new cultivated species were created, e.g., Russian plum (P. rossica Erem.), which is widely used in plantings. Such varieties are characterized by an attractive appearance, large size, pleasant aroma, and great flavor of fruits, as well as resistance to frost and rotting.

Haplotype-resolved genome assembly for tetraploid Chinese cherry (Prunus pseudocerasus) offers insights into fruit firmness.

Chinese cherry (Prunus pseudocerasus) holds considerable importance as one of the primary stone fruit crops in China. However, artificially improving its traits and genetic analysis are challenging due to lack of high-quality genomic resources, which mainly result from difficulties associated with resolving its tetraploid and highly heterozygous genome. Herein, we assembled a chromosome-level, haplotype-resolved genome of the cultivar 'Zhuji Duanbing', comprising 993.69Mb assembled into 32 pseudochromosomes using PacBio HiFi, Oxford Nanopore, and Hi-C. Intra-haplotype comparative analyses revealed extensive intra-genomic sequence and expression consistency. Phylogenetic and comparative genomic analyses demonstrated that P. pseudocerasus was a stable autotetraploid species, closely related to wild P. pusilliflora, with the two diverging ~18.34 million years ago. Similar to other Prunus species, P. pseudocerasus underwent a common whole-genome duplication event that occurred ~139.96 million years ago. Because of its low fruit firmness, P. pseudocerasus is unsuitable for long-distance transportation, thereby restricting its rapid development throughout China. At the ripe fruit stage, P. pseudocerasus cv. 'Zhuji Duanbing' was significantly less firm than P. avium cv. 'Heizhenzhu'. The difference in firmness is attributed to the degree of alteration in pectin, cellulose, and hemicellulose contents. In addition, comparative transcriptomic analyses identified GalAK-like and Stv1, two genes involved in pectin biosynthesis, which potentially caused the difference in firmness between 'Zhuji Duanbing' and 'Heizhenzhu'. Transient transformations of PpsGalAK-like and PpsStv1 increase protopectin content and thereby enhance fruit firmness. Our study lays a solid foundation for functional genomic studies and the enhancement of important horticultural traits in Chinese cherries.

Features of in vitro multiplication of stone fruit crops

Features of in vitro multiplication of stone fruit crops

Prevalence of stone fruit viruses in Russian regions and genetic analysis of PNRSV isolates

As part of monitoring works carried out by specialists of the All-Russian Plant Quarantine Center, samples of stone fruit crops collected in 20 Russian Federation subjects were tested by enzyme immunoassay for the presence of the following viruses: ACLSV, ApMV, APLPV, ArMV, CLRV, CRLV, PBNSPaV, PDV, PNRSV, PPV, PRMV, RpRSV, SLRSV, TBRV, ToRSV, and TRSV. The distribution of plum pox potyvirus (PPV), prunus necrotic ring spot ilarvirus (PNRSV), and prune dwarf ilarvirus (PDV) was determined across the area of 12, 12, and 8 Russian Federation subjects in 14.9 %, 11.9 %, and 1.7 % of test samples, respectively. The presence of these viruses was confirmed by polymerase chain reaction with subsequent sequencing of the amplification products obtained. The occurrence of these viruses was analyzed depending on the type of plantation, plant species, and region of distribution. The envelope protein gene region of 18 PNRSV isolates from five Russian Federation subjects was analyzed, which showed a significant genetic variability of this virus among the Russian population.

Optimization of clonal micropropagation of stone fruit crops

The aim of the research was to optimize the clonal micropropagation of stone crops through the use of improved techniques. The objects of the research at the stage of introduction into culture in vitro were meristematic apexes, at the stage of micro-propagation itself – micro-shoots, at the rooting stage – rooted micro-shoots, at the adaptation stage – micro-plants. All experiments were carried out according to generally accepted methods using the example of the steppe cherry variety Shchedraya, the domestic plum variety Kazanskaya and the hybrid sweet cherry Fatezh. As a result of the research, it was found that the use of a 10 % chlorhexidine solution for sterilization of the initial plant material of stone crops increased the survival rate of apexes on average by 2.4 %; the combined use of growth regulators 6-benzylaminopurine 0.5 mg/l, gibberellic acid 0.2 mg/l, indo-lil-3-butyric acid (IBA) 0.2 mg/l in a nutrient medium and an experimental diode pulsed phytoirradiator in the last proliferation passage activated the proliferation of micro-shoots, increasing the reproduction coefficient of stone crops in 6 passages by an average of 0.9 pcs/explant; the addition of 1.0 mg/l (IBA ) to the nutrient medium provided an increase in the rooting capacity of micro-shoots of stone crops by an average of 9.6 %. The treatment of micro-plants of stone crops at the stage of adaptation by spraying with an 8 % solution of the extract of the products of the larvae of the large wax moth and the use of an experimental LED pulsed phytoirradiator with a mixed spectrum contributed to an increase in their survival rate by an average of 12.4 %. Compliance with the proposed improved methods of clonal micropropagation of stone crops using growth regulators and an experimental LED pulse phytoirradiator with a mixed spectrum made it possible to increase the yield of standard adapted micro-plants by 2 times. At the same time, the cost of one adapted micro-plant decreased by an average of 11.4 rubles, and the profitability of obtaining improved stone crop material increased by 33.7 % and amounted to 160.7 %.

Genetic Variation of Monilinia fructicola Population in Korea.

Brown rot disease, caused by Monilinia spp., poses a significant threat to pome and stone fruit crops globally, resulting in substantial economic losses during pre- and post-harvest stages. Monilinia fructigena, M. laxa, and M. fructicola are identified as the key agents responsible for brown rot disease. In this study, we employed the amplified fragment length polymorphism (AFLP) method to assess the genetic diversity of 86 strains of Monilinia spp. isolated from major stone fruit cultivation regions in South Korea. Specifically, strains were collected from Chungcheong, Gangwon, Gyeonggi, Gyeongsang, and Jeolla provinces (-do). A comparative analysis of strain characteristics, such as isolation locations, host plants, and responses to chemical fungicides, was conducted. AFLP phylogenetic classification using 20 primer pairs revealed the presence of three distinct groups, with strains from Jeolla province consistently forming a separate group at a high frequency. Furthermore, M. fructicola was divided into three groups by the AFLP pattern. Principal coordinate analysis and PERMANOVA were applied to compare strain information, such as origin, host, and fungicide sensitivity, revealing significant partition patterns for AFLP according to geographic origin and host plants. This study represents the utilization of AFLP methodology to investigate the genetic variability among M. fructicol isolates, highlighting the importance of continuous monitoring and management of variations in the brown rot pathogen.

Trichopria anastrephae: A Promising Neotropical-Native Parasitoid for Drosophila suzukii Control

Trichopria anastrephae: A Promising Neotropical-Native Parasitoid for Drosophila suzukii Control

Methyl N,N-dimethylanthranilate and ethyl propionate: repellents effective against spotted wing drosophila, Drosophila suzukii.

Spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is an economically important pest of soft and stone fruit crops. The aim of this study was to identify repellents, formulated in dispensers, which could protect crops from D. suzukii. Fourteen potential repellents were screened against summer- and winter-morph D. suzukii through electroantennography and behavioural bioassays. Repellents effective in the laboratory were tested in polytunnels to determine their efficacy in reducing catches in fruit-baited traps. Further trials of three potential repellents were conducted to determine the distances over which repellent dispensers could reduce D. suzukii emergence in a strawberry crop. All 14 chemicals screened were detected by the antennae of both D. suzukii morphs. Hexyl acetate and geosmin both elicited a significantly greater corrected EAG response in summer morphs than winter morphs. Summer-morph D. suzukii were repelled by butyl acetate, ethyl propionate, methyl N,N-dimethyl anthranilate, geosmin, methyl salicylate, DEET and benzaldehyde at one or more doses test in laboratory bioassays. Winter morphs were repelled by ethyl propionate, methyl anthranilate, methyl N,N-dimethyl anthranilate, DEET, benzaldehyde and butyl anthranilate at one or more of the doses tested in the laboratory. Ethyl propionate, methyl N,N-dimethylanthranilate and benzaldehyde repelled both morphs from fruit-baited traps in polytunnel trapping trials. Ethyl propionate and methyl N,N-dimethylanthranilate reduced emergence of D. suzukii in a strawberry crop over 3-5 m. Ethyl propionate and methyl N,N-dimethylanthranilate may protect strawberry crops against D. suzukii. Future work should test these repellents in combination with attractants in a 'push-pull' strategy. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Global Transcriptome Analysis of the Peach (Prunus persica) in the Interaction System of Fruit-Chitosan-Monilinia fructicola.

The peach (Prunus persica L.) is one of the most important stone-fruit crops worldwide. Nevertheless, successful peach fruit production is seriously reduced by losses due to Monilinia fructicola the causal agent of brown rot. Chitosan has a broad spectrum of antimicrobial properties and may also act as an elicitor that activate defense responses in plants. As little is known about the elicitation potential of chitosan in peach fruits and its impact at their transcriptional-level profiles, the aim of this study was to uncover using RNA-seq the induced responses regulated by the action of chitosan in fruit-chitosan-M. fructicola interaction. Samples were obtained from fruits treated with chitosan or inoculated with M. fructicola, as well from fruits pre-treated with chitosan and thereafter inoculated with the fungus. Chitosan was found to delay the postharvest decay of fruits, and expression profiles showed that its defense-priming effects were mainly evident after the pathogen challenge, driven particularly by modulations of differentially expressed genes (DEGs) related to cell-wall modifications, pathogen perception, and signal transduction, preventing the spread of fungus. In contrast, as the compatible interaction of fruits with M. fructicola was challenged, a shift towards defense responses was triggered with a delay, which was insufficient to limit fungal expansion, whereas DEGs involved in particular processes have facilitated early pathogen colonization. Physiological indicators of peach fruits were also measured. Additionally, expression profiles of particular M. fructicola genes highlight the direct antimicrobial activity of chitosan against the fungus. Overall, the results clarify the possible mechanisms of chitosan-mediated tolerance to M. fructicola and set new foundations for the potential employment of chitosan in the control of brown rot in peaches.

Polymorphism in cherry plum (<i>Prunus cerasifera</i>) and its significance for stone crop breeding

A gene pool of cherry plum (Prunus cerasifera Ehrh.) numbering over 1000 accessions including wild forms and released cultivars of various origins has been gathered at the Krymsk Experiment Breeding Station, a branch of VIR. The study of the morphological diversity of cherry plum, or myrobalan plum, made it possible to clarify its position within the system of the genus Prunus L., and to propose an intraspecific system composed of three subspecies: Prunus cerasifera subsp. cerasifera – the typical cherry plum, P. cerasifera subsp. orientalis (M. Pop.) Erem. et Garcov. – the oriental cherry plum, and P. cerasifera subsp. macrocarpa Erem. et Garcov. – the large-fruited cherry plum with the following several varieties: Armenian (P. cerasifera subsp. macrocarpa var. nairica (Koval.) Erem. et Garkov.), Georgian (var. georgica (Erem.) Erem. et Garcov.), Iranian (subsp. macrocarpa var. iranica (Koval.) Erem. et Garcov), Pontic (subsp. macrocarpa var. pontica (Koval.) Erem. et Garcov.), Tauric (subsp. macrocarpa var. taurica (Kost.) Erem. et Garcov.), and the red-leaved cherry plum (Pissard plum) (subsp. macrocarpa var. pissardii (Carriere) Koehne).The most important role of interspecific hybridization involving the species P. cerasifera is in the origin of a number of Prunus L. species, including domestic plum P. domestica L., Fenzl’s almond P. fenzliana Fritsch, and black apricot P. dasycarpa Ehrh., has been established.The cherry plum gene pool had been found to contain donors of a number of traits of importance for breeding, which were used to create an assortment of Russian plum (Prunus × rossica Erem., hybrid myrobalan plum) cultivars and clonal rootstocks of stone fruit crops. Among them, the Russian plum ‘Globus’, ‘Kubanskaya Kometa’, ‘Gek’, ‘Kolonnovidnaya’, ‘Iyulskaya Roza’, and clonal rootstocks ‘Kuban 86’, ‘VVA 1’, ‘Evrika 99’, ‘Best’, ‘Zarevo’ have been regionally adapted and got a wide distribution.An outstanding general combining ability was demonstrated by cherry plum cvs. ‘Pionerka’, ‘Purpurovaya’, ‘Otlichtnitsa’, ‘Ashtarakskaya 2’ and ‘Tsiteli Drosha’, which were used in breeding a number of cherry plum cultivars at the Krymsk EBS, e.g. cherry plums ‘Neberdzhaevskaya Rannyaya’, ‘Kremen’, Russian plum ‘Kubanskaya Kometa’, ‘Iyulskaya Roza’, ‘Naydena’, ‘Gek’, ‘Podarok Sad-Gigantu’, etc.Most effective was the hybridization of Crimean, Armenian and Georgian cherry plum cultivars with the Chinese plum (Prunus salicina Lindl.) ‘Burbank’, ‘Gigant’, and ‘Skoroplodnaya’. As clonal rootstocks, the hybrids of myrobalan plum with peach (‘Kuban 86’ and ‘Fortuna’ rootstocks), with cherry plum ‘Sapa’ (‘Evrika 99’ and ‘Spiker’ rootstocks), as well as with low micro-cherry (rootstock ‘Best’) and Louiseania ulmifolia (Franch.) Pachom. (rootstock ‘Upriamets’) turned out to be very valuable.

РЕЗУЛЬТАТИВНОСТЬ НАУЧНЫХ ИССЛЕДОВАНИЙ ПО ОТРАСЛЕВЫМ ПРИОРИТЕТАМ

The article presents the results of the institution’s research work obtained in 2023. Research is focused on solving problems: accelerated creation of new varieties of horticultural crops based on the mobilization of bioresource collections using molecular genetic methods and digital technologies; ensuring environmental and economic sustainability and optimal productivity of perennial agrocenoses, as well as the quality and safety of preserved plant agricultural raw materials based on biologization and digitalization of technological processes. An analysis of the effectiveness of scientific and technical activities is given according to the criteria of research, publishing, publiсation, inventive activity, innovative, educational and financial and economic activities of a scientific institution. As a result of R&D, 115 completed developments of fundamental importance have received, forming the methodological and methodical basis for the creation of scientific and technical products of a priority applied level. Fundamentally new developments in applied research in the fields of knowledge relevant to the scientific institution were 81 developments that provide improvement in the quantitative and qualitative indicators of biocenotic and production processes in fruit and vineyards, technological processes during storage and processing of agricultural products. The gene pool is preserved – 7,253 samples of fruit, berry, nut crops and grapes, replenished with 127 varieties; clones were selected and 7 donors were identified and 53 sources for creating new varieties that combine high potential productivity, winter hardiness, drought resistance, sustainability to the most harmful diseases and pests. The State Register of Breeding Achievements approved for use in 2023 in the North Caucasus (6) region includes 3 varieties of apple trees, one grape variety, one clonal rootstock of small stone fruit crops, a rose variety bred by the scientific institution. Output products are registered in the USAIS electronic accounting database in the form of intellectual property for 99 completed developments. Regulatory documentation has been developed in the form of organizational standards, technological instructions and technical conditions for 37 completed developments.

Assessing Natural Incidence of Resident Pupal Parasitoids on the Drosophila suzukii (Diptera: Drosophilidae) Population in Non-crop Fruits.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), world-renowned as spotted-wing drosophila, is an invasive pest mainly affecting healthy, soft and stone fruit crops throughout Argentinian fruit-growing regions. Natural environments overgrown by exotic feral host plants apparently favour D. suzukii proliferation. This is common in the subtropical northwestern Argentina's berry-producing region. An assemblage of resident parasitoid species has been associated with D. suzukii in crop and non-crop areas of Tucumán, the Argentina's leading berries producer and exporter. Consequently, the hypothesis that the combined action of two pupal parasitoid species, Pachycrepoideus vindemiae Rondani (Hymenoptera: Pteromalidae) and Trichopria anastrephae Lima (Hymenoptera: Diapriidae), occurring in non-crop fruit areas, has a significant impact on D. suzukii natural regulation in such invaded habitats was tested. A survey of D. suzukii puparia from both feral peach [Prunus persica (L.) Batsch] (Rosaceae) and guava (Psydium guajava L.) (Myrtaceae) fallen fruits and soil surrounding them was performed in a wilderness area of Tucumán. Abundance of D. suzukii and associated parasitoids, and parasitism levels were assessed. Whole of 3437 D. suzukii puparia were recovered; 78% and 22% were surveyed from fruits and soil underneath the fruit, respectively. Tested fruits are important D. suzukii multiplying hosts. Both P. vindemiae and T. anastrephae accounted for 99.8% of total parasitoid individuals. Pupal parasitoids contribute to the D. suzukii natural mortality, as they killed a quarter of all puparia. Mostly T. anastrephae foraged on host puparia located in the fruit and P. vindemiae in both microhabitats. This information supports an augmentative biological control strategy in non-crop areas.

The preservation and study of the biodiversity of subtropical crops are carried out in the genetic collection of the FRC SSC of RAS

The issue of preserving, replenishing, and rational utilization of biological diversity is acute worldwide. Special attention is devoted to the preservation of plant biodiversity at the Federal Research Center “Subtropical Scientific Centre of the Russian Academy of Sciences (FRC SSC of RAS)” in Sochi. A comprehensive germplasm of subtropical crops has been collected and maintained, comprising 753 cultivars. Research is conducted on the Black Sea coast of the Krasnodar Region, Russian Federation. The climatic conditions of the region correspond to the zone of humid subtropics, allowing the cultivation of many thermophilic plants. The results of the conducted research and the inventory of germplasm in 2023 have led to their categorization into 7 main collections: nut crops, citrus crops, subtropical fruit crops, seed crops, stone fruit crops, subtropical industrial crops, and berry crops. From each collection, a promising assortment has been identified for commercial orchards (54 cultivars), amateur gardeners (126), landscaping (71), as well as for scientific research (breeding, physiological, biochemical, genetic, entomological, phytopathological, etc.) (222). Wild and semi-wild relatives of cultivated plants, possessing valuable traits, are of great value and are regularly utilized in breeding studies, contributing to the maintenance of the collection.

Identification of pathogens causing brown rot of stone fruit in Cuneo province (Italy) and assessment of sensitivity to azoxystrobin, cyprodinil, fenhexamid, fludioxonil, and tebuconazole

Monilinia spp. cause brown rot and blossom blight of stone fruit. This study characterized the diversity of Monilinia spp. associated with stone fruit rots in the Cuneo province, the major fruit production area in Piedmont, and assessed their sensitivity to azoxystrobin, cyprodinil, fenhexamid, fludioxonil and tebuconazole. Species diversity was determined by PCR amplification and sequencing of isolate internal transcribed spacer (ITS) regions. Sensitivity to fungicides was determined by measuring in vitro mycelium growth on fungicide-amended media. Fifty isolates were obtained from apricot, cherry, or peach fruits with typical brown rot symptoms. Thirteen isolates were identified as M. fructicola, and 37 as M. laxa. Nine isolates of Monilinia laxa and two of M. fructicola had resistance factor (RF) values greater than 10 for different fungicides. The greatest (RF) value (48.96) was measured for azoxystrobin against the M. fructicola isolate CVG 1514. Among the M. laxa isolates, isolate CVG 1547 had the greatest RF value to cyprodinil, while isolate CVG 1709 had RF values greater than 10 for cyprodinil and tebuconazole. A systematic and wider sampling should be carried out in the Piedmont region to determine the distribution of fungicide resistant Monilinia spp. in stone fruit crops. The use of site-specific fungicides remains the most effective strategy for control brown rot, and continued monitoring for fungicide resistance within Monilinia spp. populations is recommended.

Testing a set of SSR markers to obtain the genetic profiles of common plum and cherry plum varieties and to assess the genetic similarity between hybrids obtained in remote crossing

Common plum (Prunus domestica L.) is one of the fruit crops that are particularly difficult to study genetically. Unlike most other species of the genus Prunus, it is a hexaploid species (2n=48) originating from complex interspecific hybridization, and the question of its origin is yet to be conclusively resolved. Presently, several studies are available that examine the phylogeny and systematics of the genus Prunus in general and specifically the speciation of Prunus domestica L., with the use of molecular genetics methods. Although the SSR marker method is widely adopted in the practice of studying the most important stone fruit crops, the polymorphism of SSR loci in Prunus domestica L. is rarely studied in the gene pool. The present study examined the effectiveness of 22 microsatellite (SSR) markers using common plum and cherry plum varieties bred at the Federal Horticultural Center for Breeding, Agrotechnology, and Nursery in order to obtain the genetic profiles of these varieties and develop a variety passport. In addition, this set of markers was used to evaluate the genetic diversity and genetic similarity between the varieties of common plum and cherry plum, as well as remote hybrids obtained using embryo rescue, from the collection of the Federal Horticultural Center for Breeding, Agrotechnology, and Nursery. The screening results obtained for a set of 22 SSR markers using 10 varieties and 19 hybrid specimens revealed a low level of polymorphism detected by this set and a small number of shared alleles. This set of markers was found to be inadequate to fully evaluate our sample in terms of allelic diversity, as well as genetic similarity between parental and hybrid forms. The proportion of unique genotypes that can be identified using these markers amounts to less than 50 %. The large number of overlapping fragment sizes prevents the generation of individual genetic profiles for the varieties. It was found necessary to apply and test additional markers, as well as to develop multiplex sets on their basis, which will form the basis for routine genotyping of varieties. For a more accurate and reliable estimation of fragment lengths and allele sharing, further analysis should be performed using capillary electrophoresis. The work was carried out at the Laboratory of Reproductive Biotechnology of the Federal Horticultural Center for Breeding, Agrotechnology and Nursery in 2022.

Embryo rescue in stone fruit breeding: specifics and application success

The development of stone fruit varieties that meet modern production requirements is a labor-intensive process involving low yields of progeny obtained through controlled intraspecific and interspecific hybridization, which can take up to 25 years. The non-viability of hybrid seeds is caused by the abortion of the embryo that does not have time to complete its morphophysiological development and endosperm abortion in interspecific hybrids. It is possible to preserve hybrids having a unique combination of traits by removing embryos derived from interspecific and intergeneric crossing that are unable to survive in vivo or when using conventional methods for breeding embryos at early developmental stages and placing them under in vitro conditions for further development. On the basis of literary sources, the study aims to analyze growth media, conditions of their application, and time of embryo placement under in vitro conditions designed to preserve immature embryos and create hybrids of stone fruit crops, as well as to identify the most effective in vitro embryo isolation schemes for further use in the breeding process. The analytical review used open sources containing information on the composition of the most commonly used growth media, their compositions, modifications, application conditions, time of embryo placement under in vitro conditions for common peach (Prunus persica (L.) Batsch.), common apricot (P. armeniaca L.), common plum (P. domestica L.), Chinese plum (P. salicina Lindl.), cherry plum (P. cerasifera Ehrh.), sloe (P. spinosa L.), sour cherry (P. cerasus L.), sweet cherry (P. avium (L.) L.), as well as electronic scientific libraries (eLibrary, Scopus, and Google Scholar). The performed analysis of works revealed the following media as optimal for sustaining the development of embryos: common peach – modified growth medium Woody Plant (up to 100 % of preserved embryos); common apricot – modified Monnier (up to 92.4 % of preserved embryos); sour cherry, sweet cherry, plum, and interspecific hybrids – different variants of Murashige and Skoog (over 70 % of preserved embryos). The used modifiers include 6-benzylaminopurine (6-BAP), gibberellic acid (GA), kinetin, peracetic acid, carbohydrates, L-glutamine, iron chelate, ascorbic acid, thiamine, glutamic acid, tryptophan, casein hydrolysate, etc. The time of placement under in vitro conditions varies from 28 days (sour cherry) to 99 days (common peach) depending on the crop. Stratification in the dark at +4…+5 ℃ prior to development increases the yield of viable embryos. The optimal photoperiod for in vitro embryo cultivation ranges from 12 (common peach) to 16 (cherry plum, sour cherry, sweet cherry, and interspecific hybrids) hours. As a result of selection from the fund of hybrids obtained through embryo preservation, one common peach variety (Krymskii Shedevr) and three sweet cherry varieties (Vesnyany Naspivy, Prizerka, and Uslada), recommended for the North Caucasus region, were included in the State Register of Breeding Achievements approved for use; two common plum varieties (Tulitsa and Velichavaya) were included into the Register of Protected Breeding Achievements for the Central Region.

Anthracnose of stone fruits, caused by species of the genus <i>Colletotrichum</i>

Fungi from the genus Colletotrichum in the Moscow region affect the main stone fruit crops. In the Lipetsk region and the Republic of Mari-El, these pathogens were noted on cherries. The most affected crop is cherry, which in some years can lose 50-70 % of fruits from anthracnose. Varieties Apukhtinskaya and Rusinka were the most heavily affected by anthracnose. On plum and plum-cherry, the symptoms of anthracnose appear later than on cherry and sweet cherry. The appearance of symptoms is associated with the maturation of these cultures. On the plum, infection of the ovaries with Colletotrichum spp. can also inhibit the development of fruits, and their abscission, especially if the infection of fruits occurs in conjunction with other pathogenic fungi. Molecular genetic analysis of two cultures of Colletotrichum isolated from cherry fruits showed that the cultures belong to two species. These are Colletotrichum fioriniae and Colletotrichum godetiae. Artificial infection of green plum fruits in laboratory conditions showed that two isolates of Colletotrichum sp. godetiae isolated from golden currant and cherry fruits successfully infect green plum fruits. The most effective for infection is the method of infection in the puncture of the skin of the fetus.

The Physicochemical Attributes, Volatile Compounds, and Antioxidant Activities of Five Plum Cultivars in Sichuan.

Plum (Prunus salicina Lindl.) is an important stone fruit crop in Sichuan that is increasingly in demand by consumers owing to its flavor and outstanding nutraceutical properties. The physicochemical characteristics, antioxidant capacity, and volatile profiles of five traditional and new plum cultivars in Sichuan were determined using high-performance liquid chromatography and gas chromatography time-of-flight mass spectrometry. The results showed that all plums exhibited an appropriate quality profile for fresh consumption; the new cultivar 'ZH' exhibited the highest soluble solids content, sugar-acid ratio, total phenolic content, total flavonoid content, and antioxidant capacity. High sugar-low acid properties were observed in five plum cultivars. Sucrose was the main sugar, while quinic acid and malic acid were the main organic acids. The plums were rich in volatile compounds and had specific volatile characteristics. A total of 737 volatiles were identified in the plum fruit, and orthogonal partial least-squares discriminant analysis was employed to screen 40 differential volatiles as markers for cultivar distinction. These findings offer comprehensive information on the physicochemical characteristics, antioxidant capacity, and volatile profiles of plums.