Studying wild relatives of cultivated plants in each specific region is an essential component in assessing the state of national plant genetic resources. This is especially true for the regions of the Russian Caucasus, with its tremendous diversity of plant species. This paper presents the results of exploring crop wild relatives (CWR) in natural plant communities of the Karachay-Cherkess Republic. The author conducted an inventory of CWR and analysis of their species composition in Karachay-Cherkessia. The CWR list includes 516 species belonging to 134 genera of 36 families; in this list, 449 species from 107 genera of 33 families are native to this region. The Dzheguta floristic district is the richest in CWR species diversity (391 species). There are 350 and 346 species in the Arkhyz and Uchkulan districts, respectively, and 301 species in the Cherkessk district. Species were ranked according to their agricultural value and economic importance: the 1st rank was assigned to 149 plant species, 2nd rank to 17, 3rd rank to 32, 4th rank to 97, and 5th rank to 222 species. In the context of their economic use, the species for feed (158) and food (136) purposes dominated over those for medicinal (60), melliferous (54), ornamental (53), industrial (51), and revegetation (5) applications. The list of priority conservation species was compiled for CWR of Karachay-Cherkessia according to the criteria of rarity and vulnerability, based on the analysis of the CWR species distribution over the studied area and their assessment for useful economic and biological traits. A map showing localities of these species within the Republic is presented, and recommendations are given for their effective conservation.

Background. The temperature regime has a significant effect on the enzymatic activity of seeds. Optimum temperatures trigger physical and chemical reactions in the seed and initiate its germination. The optimum temperature depends on the environmental and geographical conditions in the area of a taxon’s origin and is determined experimentally.
Materials and methods. The target material of the study were seeds of three Astragalus L. species (A. cicer L., A. onobrychis L., and A. sulcatus L.) collected from young generative plants introduced in the dry-steppe zone of Kulunda. The effect of temperature conditions (+4…+8°C, +10…+20°C, +20…+32°C) and species-specific attribution of Astragalus plants on laboratory seed germination percentage and energy was studied using the two-factor analysis of variance. The assessment of laboratory seed germination was carried out according to the guidelines by M. M. Ishmuratova and K. G. Tkachenko.
Results. The analysis of variance showed a significant effect of the temperature regime (51–54%) and species specificity (23–24%) on the germination percentage rate and germination energy of Astragalus seeds. The seeds of A. onobrychis germinated under a wide range of positive temperatures (from +4…+8°C to +20…+32°C). The temperature range of +10…+20°C was optimal for A. onobrychis and A. sulcatus, with 100% germination. The optimum temperature that determined the maximum laboratory germination of A. cicer seeds was in the range of +20…+32°C. Low positive temperatures (+4…+8°C) were not effective for germination of A. cicer seeds.
Conclusion. The optimum temperature conditions for germination of Astragalus seeds were identified: +10…+20°C for A. onobrychis and A. sulcatus, and +20…+32°C for A. cicer.

Background. Paratypic variability of the development rates of barley accessions from the Republic of Dagestan was analyzed for five years in the Northwe st of Russia (Pushkin, St. Petersburg) and in the North Caucasus (Derbent, Dagestan). Responses to vernalization, photoperiodism and earliness per se were tested in contrasting environments to assess their effect on barley development. Such studies make it possible to identify valuable adaptable plant forms in the barley germplasm collection for further use in breeding practice.
Materials and methods. In Dagestan, the duration of the period from shooting to heading was measured for 12 samples of barley accessions in winter and spring sowing trials. Twenty samples sown in spring in both regions were compared. An empirical indicator of plant development rate was used for barley: the criterion “the number of days by which the period from shooting to heading of an accession exceeds the minimum across a sample” (DPSH).
Results and conclusions. Early barley accessions with a low norm of responsiveness were identified: k-3772, k-15013, k-15034, k-15036, k-15186, k-15192, k-21803 and k-23785 – they combined weak sensitivity to a short photoperiod and vernalizing temperatures, so they are promising for breeding in regions where the length of the growing season is a limiting factor. The effect of the responses of barley accessions from Dagestan to vernalization and a short photoperiod on the duration of the period from shooting to heading was on average 8 (5.1–10.6) days and on their earliness per se 6 (4.8–8.2) days. Paratypic variability reflects the range of variation for these indicators. In Dagestan, vernalization temperatures and insensitivity to a short day are the main factors determining the earliness of local barleys in their native environment.

Background. Chufa is one of the most promising rare oilseed crops. The issues of preserving and obtaining highquality seed material are very important. The development of long-term genebank storage techniques for chufa nodules is a pressing task.

Materials and methods. We studied 18 chufa germplasm accessions of various origin. The field study was conducted in 2010–2012 under the environmental conditions of Krasnodar Territory, Russia. Protein and oil content was analyzed according to the guidelines on the methods of quality control and safety of bioactive food additives (R 4.1.1672-03…, 2004); vitamin E according to the guidelines on the methods of analyzing the quality and safety of food products (Skurikhin, Tutelyan, 1987); fatty acid composition in line with IUPAC (1979) and GOST R 512677-2006, using an IIRGCS chromatograph.

Results and conclusions. The study of valuable agronomic characters in chufa accessions showed that the height of plants varied from 49 to 69 cm; the number of nodules per plant from 80 to 110 pcs; the weight of nodules per plant from 18 to 49 g; the weight of nodules per plot (1 m² ) from 101 to 393 g. Their oil content varied from 13.1 to 21.06 g/100 g, and protein content from 6 to 10%. Chufa accessions contained large amount of vitamin E: 19.23 to 35.23 mg/100 g. The content of saturated fatty acids in chufa oil was 17.75 to 20.99%, monounsaturated fatty acids from 68.21 to 71.55%, and polyunsaturated fatty acids from 9.94 to 12.17%. A technique of preparing chufa nodules for long-term storage was developed. The optimal time to assess germination energy is four days, with 11 days for germination percentage. Storage of chufa nodules for three years at a temperature of +20°C causes a decrease in their germination by 15–16%. When stored under low positive (+4°C) or negative temperatures (–18°C and –196°C), their germination percentage remained unchanged.

Background. One of the global problems presently faced by humanity is obesity and overweight. For treatment and prevention of this disease, doctors recommend consuming more vegetables, cucumbers in particular. Despite the fact that Russia is one of the major cucumber producers, its average yield is more than twice lower than in the EU countries. To meet the demand of the population, it is necessary to additionally import the missing products. In this regard, the urgent need for an increase of cucumber production is obvious, and first of all, by raising the yield.
Materials and methods. The research was conducted at the experimental sites of Volgograd Experiment Station of VIR. Accessions from VIR’s cucumber collection served as the material for the study. Methods developed and accepted by VIR were used in the research.
Results and conclusions. Such agronomic characteristics as yield, fruit weight and length, thorn color, dry matter and sugar content were studied. A noticeable direct correlation was found between fruit length and fruit weight, and moderate direct correlations were observed between yield and fruit length, yield and fruit weight, dry matter and sugars. The indicators showing suitability of accessions for salting and canning were analyzed. Accessions that can be used in breeding practice are recommended. A conclusion is made about the prospects of breeding for valuable agronomic traits using long-fruited forms of cucumber from the countries of South-East Asia and the Russian Far East.

Background. Improving the taste and nutritional value of sweetcorn using genetic selection techniques is an important trend. The tetraploid sugary maize cultivar ‘Baksanskaya sakharnaya’ (k-23426) has a number of advantages in terms of taste and marketability over traditional diploid varieties.
The purpose of the research was to identify the distinctive biochemical characteristics that affect the taste of this cultivar in comparison with the diploid reference (cv. ‘Rannyaya Lakomka’, с-1775).
Materials and methods. The differences in phenotypic traits between diploid (2n) and tetraploid (4n) maize plants were assessed. Infrared spectroscopy was used to study the difference in the biochemical composition of kernels in terms of protein, starch and oil content. Accumulation of metabolites in a dry kernel was studied using gas–liquid chromatography with mass spectrometry.
Results. Comparison of the phenotypic traits in 2n and 4n sweetcorn plants showed that 4n had a better ear structure, protein and oil content. Analysis of metabolites showed that quantitative indicators of chemical components changed in kernels of the 4n sweetcorn without changing the qualitative composition. The chemical composition of the metabolites in 4n sweetcorn grain was characterized by an increase in the synthesis of most organic acids and protein amino acids, phosphoric acid, fatty acids, some monosaccharides, phenolic compounds, and phytosterols. A decrease in the content of most polyhydric alcohols, disaccharides, trisaccharides, some monosaccharides, and phenolic compounds was observed. An inhibitory effect of a su2 gene dose on the size of starch granules was found. 
Conclusion. The studies showed the advantage of the 4n sweetcorn over the 2n one due to its improved ear structure and biochemical composition, which positively affected the taste qualities.

The immune North American grapevine species Vitis rotundifolia Michaux (subgen. Muscadinia Planch.) is regarded as a potential donor of disease resistance genes, withstanding such dangerous diseases of grapes as powdery and downy mildews. The cultivar ‘Dixie’ is the only representative of this species preserved ex situ in Russia: it is maintained by the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) in the orchards of its branch, Krymsk Experiment Breeding Station. Third-generation sequencing on the MinION platform was performed to obtain information on the primary structure of the cultivar’s genomic DNA, employing also the results of Illumina sequencing available in databases. A detailed description of the technique with modifications at various stages is presented, as it was used for grapevine genome sequencing and whole-genome sequence assembly. The modified technique included the main stages of the original protocol recommended by the MinION producer: 1) DNA extraction; 2) preparation of libraries for sequencing; 3) MinION sequencing and bioinformatic data processing; 4) de novo whole-genome sequence assembly using only MinION data or hybrid assembly (MinION+Illumina data); and 5) functional annotation of the whole-genome assembly. Stage 4 included not only de novo sequencing, but also the analysis of the available bioinformatic data, thus minimizing errors and increasing precision during the assembly of the studied genome. The DNA isolated from the leaves of cv. ‘Dixie’ was sequenced using two MinION flow cells (R9.4.1).

Background. An important consumer trait of strawberry fruits is their aroma. Methyl anthranilate makes a considerable contribution to the fruit flavor. The methyl anthranilate content in strawberry fruits is controlled by the FanAAMT (аnthranilic acid methyltransferase) gene. Identification of genetic determinants for this trait facilitates targeted selection of promising forms based on diagnostic DNA markers. The purpose of this study was to study the allelic diversity of the FanAAMT fruit flavor gene in wild strawberry species and strawberry cultivars for identification of promising genotypes.
Materials and methods. The objects of this study were wild species of Fragaria L. as well as F. × anaschata Kantor. and F. × ananassa Duch. cultivars of different ecogeographic origin. The FanAAMT gene was identified with the dominant marker FanAAMT.
Results and conclusion. In the analyzed collection of strawberry genotypes, the FanAAMT gene was identified in 36.4% of the forms, including the wild species F. vesca L., F. moschata Duch. and F. virginiana subsp. platypetala (Rydb.) Staudt, and cv. ‘Kupchikha’ (F. × anaschata). Among the analyzed F. × ananassa cultivars, the FanAAMT gene was found in 31.6% of the tested forms, specifically in 27.3% of the 22 Russian cultivars, and 37.5% of the analyzed foreign ones. Promising sources of high methyl anthranilate content in fruits were identified: wild spp. F. moschata, F. vesca, and F. virginiana subsp. platypetala; cv. ‘Kupchikha’ (F. × anaschata); Russian garden strawberry cvs. ‘Bylinnaya’, ‘Zenit’, ‘Lastochka’, ‘Neznakomka’, ‘Feyerverk’ and ‘Tsarskoselskaya’; and foreign garden strawberry cvs. ‘Karmen’, ‘Ostara’, ‘Samson’, ‘Symphony’, ‘Troubadour’ and ‘Vima Tarda’, in which the functional allele of the FanAAMT gene was found. In the remaining studied strawberry genotypes the marker FanAAMT was not detected, which presumably indicates that the FanAAMT gene is absent. cells (R9.4.1).

Background. Development of early-ripening spring bread wheat (Triticum aestivum L.) cultivars is an important task for Russian breeders. Knowledge of the genetics of ultraearly varieties – sources of valuable genes that determine an earlier-maturing type of plant development –will be used to work out methods for obtaining source material for breeding.
Materials and methods. The ultra-early lines Rico (k-65588, var. erythrospermum Koern.) and Rimax (k-67257, var. lutescens (Alef.) Mansf.), and cvs. ‘Max’ (k-57181, var. lutescens) and ‘Leningradskaya 6’ (k-64900, var. lutescens) were studied. Alleles of the Vrn and Ppd genes were identified by PCR according to known publications, and genomic DNA was isolated from 3-day-old seedlings by the CTAB method.
Results. In the environments of Northwest Russia, the Rimax and Rico lines are characterized by the highest rate of development before heading among the spring wheat accessions from the VIR collection. In the Rimax and Rico genotypes, the Vrn-A1, Vrn-B1, Vrn-D1 and Ppd-D1 genes were found. Genotypes with different alleles of Ppd-D1 and Vrn-B1 were identified in the Rimax line. Under conditions of a long day (18 hours), in the population of F₂  (F₃) Rico × Rimax hybrids, the ratio of phenotypes with a high development rate to all others was observed as 1 : 15 (χ² _{1: 15} = 0.64). Under a short day (12 hours), 5 clearly tested groups were identified in F₂ with the ratio 1 : 4 : 6 : 4 : 1 (χ²  = 3.03; χ² _0.05 = 9.48), which indicates the manifestation of cumulative polymerization.
Conclusion. Each of the Rimax and Rico lines has two pairs of independent duplicated genes that determine a high development rate. Under short-day conditions, these genes can interact like cumulative polymers. The Rimax and Rico lines, due to their high development rate, are valuable source material to be used in breeding for earliness.

Background. In cereals, photosynthetically active parts of the ear significantly contribute to seed size and weight at the grain-filling stage. In barley, ear tissues may accumulate melanin pigments synthesized in chloroplast-derived melanoplasts. Effects of such pigments on yield parameters of seeds have not been evaluated to date.
Materials and methods. Seed weight and size assessed by image analysis were compared between two near-isogenic barley lines differing in alleles of the Blp1 gene, which determines melanin accumulation in ear tissues. Data on grainrelated parameters were collected during 6 years and include data on seeds grown either in the field or under greenhouse conditions.
Results and discussion. A negative effect of the Blp1 locus on the weight of 1000 seeds harvested in the field but not in the greenhouse was revealed. To determine whether this effect is related to grain size, a comparison of two-dimensional linear parameters of seeds between the lines was performed. It was shown that unlike the length and the area of seeds, the width of seeds was also negatively affected by the Blp1 locus. Although the same factors affected the weight of 1000 seeds and the width of seeds, a correlation between them was not found, implying a dependence of seed weight on other factors such as thickness and its related parameter, seed volume.
Conclusion. Effects of barely ear pigmentation and of the gene controlling it on yield-related parameters of seeds were studied here for the first time. The observed negative impact of the Blp1 locus on seed weight and size may be mediated by an interfering chloroplast activity and/or accumulation of assimilates via melanogenesis. Additional studies are necessary to test this supposition and to investigate the interaction of melanin synthesis and photosynthetic activity of the tissues accumulating this pigment.

Expanding the assortment through the development of new highly adaptable cultivars is the main task of pear breeding in the Middle Urals. The most significant agronomic traits are winter hardiness, high fruit yield, and good fruit quality. The zoned pear assortment for the Middle Urals includes six cultivars. Six more cultivars now undergo the State Variety Trials. One of them is the new pear cultivar ‘Tais’ (breeding number DL-33-104), the result of crossing Dyuymovochka × Zhanna d’Ark. Cv. ‘Tais’ has been in variety studies at Sverdlovsk Horticultural Breeding Station (Yekaterinburg) since 2006. The new cultivar is characterized by good winter hardiness and productivity. The average yield at the age of 10–14 years is 9.42 tons per hectare, while the maximum yield is 19.81 t/ha. Fruits are yellow, with a good sweet taste, weighing 94 g. The content of dry matter is 11.9%, sugars 9.0%, and titratable acids 0.4%. According to the results of long-term research, the new pear cultivar ‘Tais’ was submitted to the State Variety Trials in 2017.

Background. The presented information refers to the completed stage of the breeding process carried out at the Institute of Agrobiotechnologies (Syktyvkar) that led to the development of a new mid-early table potato variety – ‘Vychegodsky’. This cultivar was obtained from controlled crossing of cvs. Svitanok Kievsky × Amadeus. The new variety underwent a comprehensive assessment for the main agronomic traits and genetic screening for resistance to wart disease, nematode, and viruses X and Y.
Materials and methods. In 2020, according to the results of production tests performed in 2017–2019, the description of the new cv. ‘Vychegodsky’ was finalized. The registered cv. ‘Nevsky’ was chosen as the reference. The study was conducted in the Institute’s experiment fields with a six-field crop rotation, which ensured high soil fertility without the use of mineral or organic fertilizers. The soil was soddy-podzolic. The planting scheme was 70 × 30 cm, at a depth of 8–10 cm, over the experimental plot area of 52.5 m²  (250 tubers), with four replications.
Results. The mid-early cultivar ‘Vychegodsky’ is described as follows: the plant is erect, 50–65 cm in height; tubers are roundish-oval, with yellow skin color and light yellow flesh. The studies have shown that in its agronomic traits in the Republic of Komi cv. ‘Vychegodsky’ exceeds the reference cv. ‘Nevsky’. Its yield is 34.3 t/ha, and its marketable tuber weight 55.1 g; it contains 15.7% of starch, 24.1% of dry matter, and 11.2 mg% of vitamin C. The cultivar demonstrates high field resistance to major potato diseases, and genetically determined resistance to wart disease and golden potato nematode.
Conclusion. Thus, a new potato cultivar has been released and included into the State Register of Selection Achievements (National List of the Russian Federation).

Background. An urgent problem is the development and introduction of cultivars for universal use that can meet the demand of animal husbandry for various types of feed and that of food industry for raw materials. Of great interest in this regard is ‘Tobolyak’, a new spring oat cultivar characterized by a high yield of grain and green biomass.
Materials and methods. The cultivar was developed at the Research Institute of Agriculture for the Northern TransUrals, a branch of the Tyumen Scientific Centre, Siberian Branch of the RAS, using hybridization techniques with subsequent selection. The cultivars used as source material for hybridization were ‘Tayoznik’ (Narym Agricultural Station, Tomsk Province) and ‘Orion’ (Siberian Research Institute of Agriculture, Omsk Province).
Results. It is a mid-ripening cultivar, with the growing season of 71 to 83 days from sprouting to wax ripeness; its plants are medium-tall (89.6 to 120.2 cm), and resistant to lodging. The average grain yield for the years of study (2014–2019) under the environmental conditions of the northern forest-steppe (Tyumen Province) was 5.88 t/ha (+0.41 t/ha to the reference). The maximum grain yield (7.97 t/ha) was obtained in 2019 at the Lower Tavda Variety Testing Plot, Tyumen Province. The cultivar formed a grain with the test weight of 459.5–527.0 g/l and a low hull content of 22.1–25.1%. The yield of green biomass varied from 31.4 to 47.3 t/ha, depending on the growing conditions, and averaged 37.7 t/ha in 2014–2019 (+7.3 t/ha to the reference). Dry matter harvest averaged 11.76 t/ha (+1.54 t/ha to the reference), ranging from 8.62 to 14.56 t/ha.
Conclusion. The new spring oat cultivar ‘Tobolyak’ for universal use has been listed the State Register for Selection Achievements since 2020 and recommended for cultivation in regions 10, 11 and 12 of the Russian Federation.

Background. Tinomiscium petiolare Hook.f. & Thomson is a medicinal species of the family Menispermaceae. This species is currently being intensively exploited for therapeutic purposes. Precise and rapid identification of T. petiolare is critical and essential for the classification, propagation, use and conservation of its genetic resources. In recent years, DNA barcoding has been known to be a fast and sensitive method for identifying species at any stage of development, using short DNA sequences. In this study we have performed the identification of T. petiolare specimens in Vietnam based on the sequence analysis of 4 DNA barcode loci: ITS, matK, rbcL and rpoC.
Materials and methods. Total DNA was extracted from leaf samples using DNeasy Plant Mini Kit. PCR amplification of the ITS, matK, rbcL and rpoC regions was carried out on the GeneAmp PCR System 9700 with specific primers. The purified PCR products were sequenced on the ABI 3500 Genetic Analyzer system, using BigDye®Terminator v3.1 Cycle Sequencing Kit. These genetic sequences were analyzed and compared, and a phylogenetic tree was constructed using BioEdit, BLAST, and MEGA 6 programs.
Results and conclusion. The success rate of amplification and sequencing was 100% for all 4 DNA barcode loci (ITS, matK, rbcL and rpoC) in the studied specimens. The produced sequence sizes of ITS, matK, rbcL and rpoC in the specimens were 574 bp, 810 bp, 527 bp and 488 bp, respectively. Further, we identified that all studied specimens were genetically related to each other and associated with the same species T. petiolare. Overall, the results of the study generated the most complete DNA barcode database of T. petiolare collected in Vietnam, contributing to the taxonomy and identification of this species. 

Background. The grain coat plays a major role in the development of rye cultivars with low levels of water-soluble pentosans (WSP). Grain coat thinness is a diagnostic trait for low WSP (arabinoxylans) content. To improve the technology of low-pentosan rye breeding, it becomes important to study the effect of changes in the anatomy of low-pentosan grains on morphological characteristics.
Materials and methods. Grains with thin coats (transparent) were identified with the LFS-1 diaphanoscope in the populations of 7 commercial winter rye cultivars grown in Russian Federation. Anatomical and morphological features of seed coats were studied on thick- and thin-coated grains identified in the rye cultivars ‘Era’ and ‘Vyatka’. The thickness of grain coats and the aleurone layer were assessed according to L. N. Lyubarsky.
Results and conclusions. In thin-coated rye grains, we found a reduction in the thickness of the pericarp and seed coats by 50–70% and in the aleurone layer by 32.1–39.6%, compared to thick-coated grains. With a constant cell size in “transparent” grains, a decrease in the thickness of the aleurone layer and coat occurs at the expense of the reduction in not only the cell walls, but also the intercellular space. The pericarp in the tissues of the second multicellular layer contains the bulk of the protective biologically passive WSP. It was proved that there were no significant changes in grain parameters, such as length, width and relative volume, depending on coat thinness. Significant differences were found in the 1000 grain weight. In “transparent” grains the index increased by 5.2–19.7%, compared with “nontransparent” ones. 

Background. Stem rust of wheat, caused by the biotrophic fungus Puccinia graminis Pers. f. sp. tritici Eriks. et Henn., is a dangerous disease that afflicts serious economic damage to the cultivation of durum wheat.
Materials and methods. Cultivars and promising materials developed at the Spring Durum Wheat Breeding Laboratory, Omsk Agrarian Scientific Center (OASC), lines obtained under the CIMMYT and KASIB programs, and accessions from the VIR collection were the objects of research. Field experiments, phenological observations, and assessment of stem rust resistance were carried out from 1990 through 2019 in the OASC experimental fields using conventional methods. Resistance to the Ug99 race was evaluated under natural infection pressure at the Kenya Agricultural and Livestock Research Organization (KALRO).
Results. Promising source material was identified and included in the Laboratory’s breeding program. The ways were shown to develop stable cultivars of spring durum wheat for the environments of Western Siberia. A strategy was proposed for the selection of genotypes in hybrid combinations of spring durum wheat: it would include early selection (starting from F₂) for disease resistance with simultaneous screening for quantitative traits and pasta-making qualities. The description and advantages of cv. ‘Omsky korall’, submitted to the State Variety Trials in 2018, are presented. This cultivar combines high yield, adaptability, resistance to the local population and the Ug99 race of the stem rust pathogen, and excellent pasta-making qualities.
Conclusion. As a result of these studies under heavy stem rust pressure in Western Siberia, all breeding nurseries obtained source material resistant to the Omsk population of P. graminis. The released cultivars ‘Omskaya yantarnaya’ and ‘Omsky izumrud’ demonstrate resistance to the Omsk population of the stem rust causative agent.

The concept of “the weed flora” is still associated with weedy plants within agricultural phytocenoses, despite the fact that its association with a wider range of secondary habitat types with disturbed vegetation and soil cover was discussed as early as in the first half of the last century. The study of this characteristic feature of weeds has been continued at the present time, which is reflected in the very concept of “the weed” adopted by the state standards. The structure of the weed flora includes groups of weedy plant species within both naturally and anthropogenically disturbed habitats, so such notions as “the segetal flora” or “synanthropic flora” do not fully reflect the composition of the weed flora. The formation of the weed flora was historically linked with the emergence and development of cultivated plants. A regional weed flora is composed of weed plant species, for which this or that region is suitable in terms of growing conditions. In the context of agriculture and plant protection, the elementary weed flora is the flora of an agricultural landscape or an agricultural ecosystem, as its component. Phytosanitary zoning for a set of weed species confined to a specific territory is carried out at the macro-, meso-, and microlevels. The criterion for identifying the levels of phytosanitary zoning is the weed flora of different territorial levels.

Among the chronicles relating the heroism of the besieged Leningrad, there are pages dedicated to the deeds performed by the staff the world-famous All-Union Research Institute of Plant Industry (VIR, now the N.I. Vavilov All-Russian Institute of Plant Genetic Resources). With the beginning of the war, even before the city was surrounded by the Nazi troops, the government decided to evacuate a number of factories and institutes from Leningrad, including VIR, but the plan failed. Only in winter did the Institute start partial evacuation, although preparations had been going on for a long time. The largest and most important part of the collection was left behind in the besieged city. The remaining employees were forced to work under the hardest conditions of the siege, in unheated premises. In the harsh reality of the winter in 1941–1942, the daily bread rationing was cut down, and hunger raged in the city, killing tens of thousands of city residents, including VIR employees who kept the stored seeds and tubers untouched. The most difficult part was preserving the potato collection. In the spring of 1942, preparations were made for sowing to restore the viability of seeds and tubers in the fields of Leningrad’s suburban area under the fire from the enemy artillery. Only the heroic efforts of VIR’s staff helped to save the collection from destruction and loss of germination. This heroism cost more than 20 experts and scientists their lives. So, the most dangerous period for the Institute was overcome at such price. Immediately after the siege was lifted, a group of experts was sent to Leningrad from Krasnoufimsk to help with selecting seed accessions for urgent reproduction. Working under extreme physical exhaustion in frozen premises, without water or electricity, under continuous shelling, they saved, many at the cost of their own lives, the collection of cultivated plants and their wild relatives, the herbarium, and the scientific library for future generations. 

Porfiry Afanasyevich Dibrova was one of the first scientists and breeders standing at the origins of scientific pomiculture in the Urals. He was the author of 23 cultivars of apple, six of pear, one of sour cherry, and one of black currant. In the 1940s, he was the leader of collecting missions exploring the local assortment of fruit and berry crops in 50 districts of Sverdlovsk and Molotov (Perm) Provinces, and the Udmurt Republic. P.A. Dibrova was one of the authors of the first standard set of fruit and berry cultivars for the abovementioned areas. He studied regularities in the inheritance of valuable agronomic and biological traits of fruit crops and identified promising sources for apple and pear breeding. He launched the main plant breeding trends in the Middle Urals, now followed by contemporary breeders: the development of highly winter-hardy cultivars of apple and pear with fruiting precocity, stable yields, excellent fruit quality, and improved biochemical composition in fruits.