[Improvement of Crops Using the CRISPR/Cas System: New Target Genes].

The success of genome editing of crops using the CRISPR/Cas system largely depends on the correct choice of target genes, for which directed changes will increase yield and improve the quality of plant raw materials and resistance to biotic and abiotic stress factors. This work systematizes and catalogs data on target genes used to improve cultivated plants. The latest systematic review examined articles indexed in the Scopus database and published before August 17, 2019. Our work covers the period from August 18, 2019 to March 15, 2022. A search according to the given algorithm allowed us to identify 2090 articles, among which only 685 contain the results of gene editing of 28 species of cultivated plants (the search was carried out for 56 crops). A significant part of these papers considered either editing of target genes, which was previously carried out in similar works, or studies related to the field of reverse genetics, and only 136 articles contain data on editing of new target genes, whose modification is aimed at improving plant traits important for breeding. In total, 287 target genes of cultivated plants were subjected to editing in order to improve properties significant for breeding over the entire period of the CRISPR/Cas system application. This review presents a detailed analysis of the editing of new target genes. The studies were most often aimed at increasing productivity and disease resistance, as well as improving the properties of plant materials. It was noted whether it was possible to obtain stable transformants at the time of publication and whether editing was applied to non-model cultivars. The range of modified cultivars of a number of crops has been significantly expanded, in particular, for wheat, rice, soybean, tomato, potato, rapeseed, grape, and maize. In the vast majority of cases, editing constructs were delivered using agrobacterium-mediated transformation, less commonly, using biolistics, protoplast transfection, and haploinducers. The desired change in traits was most often achieved by gene knockout. In some cases, knockdown and nucleotide substitutions in the target gene were carried out. To obtain nucleotide substitutions in the genes of cultivated plants, base-editing and prime-editing technologies are increasingly used. The emergence of a convenient CRISPR/Cas editing system has contributed to the development of specific molecular genetics of many crop species.

[Genome Editing in Species of the Tribe Triticeae with the CRISPR/Cas System].

The tribe Triticeae includes important agricultural crops, such as bread wheat, durum wheat, barley, rye, and triticale. Research in the field of reverse genetics and genetic engineering of Triticeae received a new impetus as the CRISPR/Cas genome editing system came into broad use. The review describes and analyzes the data on recent advances in genomic editing of cultivated plants of the tribe Triticeae and tools used in the field. The tools most commonly used for genome editing in Triticeae include the codon-optimized Cas9 gene under the control of the maize ubiquitin gene promoter and guide RNAs under the control of Pol III promoters U6 and U3 in one or more binary vectors. Phosphinothricin and hygromycin resistance genes are used as selectable genes. Agrobacterium-mediated transformation and biolistics are performed to obtain genome-edited plants, and immature embryos are used as explants. Approaches developed to overcome the problem of low regenerative capacity of Triticeae include in planta transformation of shoot apical meristems, transformation of microspores and pollen grains, and the use of haploinductors. Bread wheat and barley were subject to genomic editing in the majority of studies published to date, and durum wheat and triticale were recently used in CRISPR/Cas knockout studies of target genes. Further progress in the development of genome editing of cultivated plants of the tribe Triticeae should be aimed at expanding the range of species and varieties involved and overcoming the problems of low regenerative capacity. This will allow genetic modification of elite varieties, which will be in demand in agricultural production.

[Anthocyanins as functional food components]. / Антоцианы как компоненты функционального питания.

Among the natural pigments, anthocyanins are assumed to represent one of the most studied groups. Starting with the first studies on the physicochemical properties of anthocyanins carried out in the 17th century by British naturalist Robert Boyle, the science about these unique compounds has progressed substantially. To date, the structure and functions of anthocyanins in plant cells have been well studied, and the pathway of their biosynthesis is one of the most fully characterized pathways of secondary metabolite biosynthesis at both the biochemical and genetic levels. Along with these fundamental achievements, we are beginning to realize the potential of anthocyanins as compounds of industrial importance, as pigments themselves, as well as components of functional food that contribute to the prevention and reduction of risk of chronic diseases. For a long time, the biological activity of anthocyanins has been underestimated, in particular, due to the data on their low bioavailability. However, studies showed that in humans and animals, these compounds are actively metabolized and the bioavailability, estimated taking into account their metabolites, exceeded 12 %. It has been experimentally shown that anthocyanins have antioxidant, anti-inflammatory, hypoglycemic, antimutagenic, antidiabetic, anti-cancer, neuroprotective properties, and they are beneficial for eye health. However, the studies conducted cannot always explain the molecular mechanism of action of anthocyanins in the human body. According to some reports, the observed effects are not due to the action of anthocyanins themselves, but to their metabolites, which can be more biologically active because of their increased bioavailability. Other data ascribe the positive effect on human health not to individual anthocyanins, but to the whole complex of polyphenolic compounds consumed. The review summarizes the results of the studies of anthocyanins as components of functional food. Special attention is paid to genetic control of the pigment synthesis. These data are of particular importance in respect to the initiated breeding programs aimed at increasing the content of anthocyanins in cultural plants.

Genotyping of potato samples from the GenAgro ICG SB RAS collection using DNA markers of genes conferring resistance to phytopathogens.

Wart (a disease caused by Synchytrium endobioticum) and golden cyst potato nematode (Globodera rostochiensis), which parasitize the roots of the host plant, cause signif icant damage to potato crop. Both of these disease factors are quarantined in the Russian Federation, and each registered variety is tested for resistance to their most common races and pathotypes. The main method of opposing such diseases is by the development of resistant varieties. An important step in this process is the selection of resistant genotypes from the population and the estimation of the resistance of hybrids obtained by crosses during the breeding process. Conducting a permanent phenotypic evaluation is associated with diff iculties, for example, it is not always possible to work with pathogens, and phenotypic evaluation is very costly and time consuming. However, the use of DNA markers linked to resistance genes can signif icantly speed up and reduce the cost of the breeding process. The aim of the study was to screen the GenAgro potato collection of ICG SB RAS using known diagnostic PCR markers linked to golden potato cyst nematode and wart resistance. Genotyping was carried out on 73 potato samples using three DNA markers 57R, CP113, Gro1-4 associated with nematode resistance and one marker, NL25, associated with wart resistance. The genotyping data were compared with the data on the resistance of the collection samples. Only the 57R marker had a high level of correlation (Spearman R = 0.722008, p = 0.000000, p < 0.05) between resistance and the presence of a diagnostic fragment. The diagnostic eff iciency of the 57R marker was 86.11 %. This marker can be successfully used for screening a collection, searching for resistant genotypes and marker-assisted selection. The other markers showed a low correlation between the presence of the DNA marker and resistance. The diagnostic eff iciency of the CP113 marker was only 44.44 %. Spearman's correlation coeff icient (Spearman R = -0.109218, p = 0.361104, p < 0.05) did not show signif icant correlation between resistance and the DNA marker. The diagnostic eff iciency of the NL25 marker was 61.11 %. No signif icant correlation was found between the NL25 marker and resistance (Spearman R = -0.017946, p = 0.881061, p < 0.05). The use of these markers for the search for resistant samples is not advisable.

[NGS sequencing in barley breeding and genetic studies]. / NGS-секвенирование в селекционно-Ð³ÐµÐ½ÐµÑ‚Ð¸Ñ‡ÐµÑÐºÐ¸Ñ Ð¸ÑÑÐ»ÐµÐ´Ð¾Ð²Ð°Ð½Ð¸ÑÑ ÑÑ‡Ð¼ÐµÐ½Ñ.

Barley (Hordeum vulgare L.) is the one of the most important cereal species used as food and feed crops, as well as for malting and alcohol production. At the end of the last century, traditional breeding techniques were complemented by the use of DNA markers. Molecular markers have also been used extensively for molecular genetic mapping and QTL analysis. In 2012, the barley genome sequencing was completed, which provided a broad range of new opportunities - from a more efficient search for candidate genes controlling economically important traits to genomic selection. The review summarizes the results of the studies performed after barley genome sequencing, which discovered new areas of barley genetics and breeding with high throughput screening and genotyping methods. During this period, intensive studies aimed at identification of barley genomic loci associated with economically important traits have been carried out; online databases and tools for working with barley genomic data and their deposition have appeared and are being replenished. In recent years, GWAS analysis has been used for large-scale phenotypegenotype association studies, which has been widely used in barley since 2010 due to the developed SNP-arrays, as well as genotyping methods based on direct NGS sequencing of selected fractions of the genome. To date, more than 80 papers have been published that describe the results of the GWAS analysis in barley. SNP identification associated with economically important traits and their transformation into CAPS or KASP markers convenient for screening selection material significantly expands the possibilities of marker-assisted selection of barley. In addition, the currently available information on potential target genes and the quality of the whole barley genome sequence provides a good base for applying genome editing technologies to create material for the creation of varieties with desired properties.

Molecular genetic bases of seed resistance to oxidative stress during storage.

Conservation of plant genetic diversity, including economically important crops, is the foundation for food safety. About 90 % of the world's crop genetic diversity is stored as seeds in genebanks. During storage seeds suffer physiological stress consequences, one of which is the accumulation of free radicals, primarily reactive oxygen species (ROS). An increase in ROS leads to oxidative stress, which negatively affects the quality of seeds and can lead to a complete loss of their viability. The review summarizes data on biochemical processes that affect seed longevity. The data on the destructive effect of free radicals towards plant cell macromolecules are analyzed, and the ways to eliminate excessive ROS in plants, the most important of which is the glutathioneascorbate pathway, are discussed. The relationship between seed dormancy and seed longevity is examined. Studying seeds of different plant species revealed a negative correlation between seed dormancy and longevity, while various authors who researched Arabidopsis seeds reported both positive and negative correlations between dormancy and seed longevity. A negative correlation between seed dormancy and viability probably means that seeds are able to adapt to changing environmental conditions. This review provides a summary of Arabidopsis genes associated with seed viability. By now, a significant number of loci and genes affecting seed longevity have been identified. This review contains a synopsis of modern studies on the viability of barley seeds. QTLs associated with barley seed longevity were identified on chromosomes 2H, 5H and 7H. In the QTL regions studied, the Zeo1, Ale, nud, nadp-me, and HvGR genes were identified. However, there is still no definite answer as to which genes would serve as markers of seed viability in a certain plant species.

The consensus rye microsatellite map with EST-SSRs transferred from wheat.

Microsatellite (SSR) markers with known precise intrachromosomal locations are widely used for mapping genes in rye and for the investigation of wheat-rye translocation lines and triticale highly demanded for mapping economically important genes and QTL-analysis. One of the sources of novel SSR markers in rye are microsatellites transferable from the wheat genome. Broadening the list of available SSRs in rye mapped to chromosomes is still needed, since some rye chromosome maps still have just a few microsatellite loci mapped. The goal of the current study was to integrate wheat EST-SSRs into the existing rye genetic maps and to construct a consensus rye microsatellite map. Four rye mapping populations (P87/P105, N6/N2, N7/N2 and N7/N6) were tested with CFE (EST-SSRs) primers. A total of 23 Xcfe loci were mapped on rye chromosomes: Xcfe023, -136 and -266 on chromosome 1R, Xcfe006, -067, -175 and -187 on 2R, Xcfe029 and -282 on 3R, Xcfe004, -100, -152, -224 and -260 on 4R, Xcfe037, -208 and -270 on 5R, Xcfe124, -159 and -277 on 6R, Xcfe010, -143 and -228 on 7R. With the exception of Xcfe159 and Xcfe224, all the Xcfe loci mapped were found in orthologous positions considering multiple evolutionary translocations in the rye genome relative to those of common wheat. The consensus map was constructed using mapping data from the four bi-parental populations. It contains a total of 123 microsatellites, 12 SNPs, 118 RFLPs and 2 isozyme loci.

Genomic regions of Solanum tuberosum L. associated with the tuber eye depth.

Potato (Solanum tuberosum L.) is one of the most important food crops in the world. The genome of this potato species is autotetraploid and has a high level of heterozygosity, also this potato species is a cross-pollinated plant. These characteristics complicate the genetic analysis and breeding process. The tuber's eye depth is an important trait that affects the suitability of potato varieties for processing. Potato breeding for this trait is based on phenotypic assessment. Identification of the loci that control tuber eye depth would allow diagnostic markers for the marker-assisted selection to be created. The aim of this study is to search for loci associated with the eye depth by analyzing Solanum tuberosum varieties from the GenAgro collection of the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, genotyped using the Illumina 22K SNP potato array DNA chip. The 24 significant markers associated with the "eye depth" trait were identified using 15,214 SNP markers genotyped with the Illumina 22K SNP potato array chip and the general linear model (GLM) taking into account the population structure. Data obtained showed the presence of SNPs in four genomic regions: on chromosome 4 (1 marker in the 3.92 Mb area), 5 (1 marker in the 4.67 Mb area) and 10 (1 marker in the 4.87 Mb area and 21 markers in the region between 48.1-48.9 Mb). The results of localization in the region 48.1-48.9 Mb of chromosome 10 correspond to previously published studies, the remaining three regions were detected for the first time. DNA sections containing SNPs linked to the tuber's eye depth were studied in the SolTub_3.0 potato genome assembly (https://plants.ensembl.org/). KASP markers were developed based on the data obtained. It will be possible to screen the breeding material and to breed the varieties more effectively using current markers associated with a shallow tuber's eye depth.

[MYC gene family in cereals: Transformations during evolution of hexaploid bread wheat and its relatives].

The transcription factors of the MYC gene family are an integral part of the MYB + MYC + WD40 regulatory complex required to activate the genes of plant flavonoid biosynthesis. The TaMyc1 gene, which controls the synthesis of flavonoid pigments in the grain pericarp, is known in bread wheat (Triticum aestivum L., BBAADD genome, 2n = 6x = 42). In the present work, we identified 10 copies of this gene in the T. aestivum genome, 22 copies in the nearest bread wheat relatives (T. durum, T. urartu, T. monococcum, Aegilops speltoides, Ae. sharonensis, Ae. tauschii). The analysis of genetic similarity of all these genes demonstrated that the MYC gene duplication occurred for the first time in the common diploid ancestor of the Triticeae tribe with the formation of copies in the second and fourth chromosomes. In the members of the Triticum and Aegilops genera, these genes underwent from two to four duplication acts that resulted in the formation of paralogous copies. The orthologs of the MYC genes obtained from ancestral diploid species exist in polyploid species of the Triticum genus (in addition to paralogues). The time of the emergence of individual MYC family members was calculated based on the average speed of accumulation of nucleotide substitutions (k) in the MYC genes (established in this work) and certain number of synonymous substitutions between individual copies.

[Prospects for application of breakthrough technologies in breeding: The CRISPR/Cas9 system for plant genome editing].

Integration of the methods of contemporary genetics and biotechnology into the breeding process is assessed, and the potential role and efficacy of genome editing as a novel approach is discussed. Use of molecular (DNA) markers for breeding was proposed more than 30 years ago. Nowadays, they are widely used as an accessory tool in order to select plants by mono- and olygogenic traits. Presently, the genomic approaches are actively introduced into the breeding processes owing to automatization of DNA polymorphism analyses and development of comparatively cheap methods of DNA sequencing. These approaches provide effective selection by complex quantitative traits, and are based on the full-genome genotyping of the breeding material. Moreover, biotechnological tools, such as doubled haploids production, which provides fast obtainment of homozygotes, are widely used in plant breeding. Use of genomic and biotechnological approaches makes the development of varieties less time consuming. It also decreases the cultivated areas and financial expenditures required for accomplishment of the breeding process. However, the capacities of modern breeding are not limited to only these advantages. Experiments carried out on plants about 10 years ago provided the first data on genome editing. In the last two years, we have observed a sharp increase in the number of publications that report about successful experiments aimed at plant genome editing owing to the use of the relatively simple and convenient CRISPR/Cas9 system. The goal of some of these experiments was to modify agriculturally valuable genes of cultivated plants, such as potato, cabbage, tomato, maize, rice, wheat, barley, soybean and sorghum. These studies show that it is possible to obtain nontransgenic plants carrying stably inherited, specifically determined mutations using the CRISPR/Cas9 system. This possibility offers the challenge to obtain varieties with predetermined mono- and olygogenic traits.

The effect of two differentially expressed wheat VRN-B1 alleles on the heading time is associated with structural variation in the first intron.

We measured the level of VRN-B1 transcripts within near-isogenic lines of Triticum aestivum cultivar 'Bezostaya 1' carrying two VRN-B1 alleles from cultivars 'Saratovskaya 29' and 'Diamant 2' (VRN-B1c and VRN-B1a, respectively). Both lines have similar kinetics of VRN-B1 transcript accumulation at the third to fifth leaf stages. However, quantitative PCR analysis at the third leaf stage showed that the VRN-B1c allele was transcribed 10 times faster than the VRN-B1a allele. The F1 hybrid between the lines is more similar to the line carrying the VRN-B1a allele with regard to the level of VRN-B1 transcription. The difference in the transcript levels of the VRN-B1 alleles appears to be due to the previously identified structural changes in the first intron of VRN-B1c (deletion of 0.8 kb and duplication of 0.4 kb) as compared with VRN-B1a, as no other differences were revealed in the present study. We suggested that the first intron structural changes in the VRN-B1c allele as compared with VRN-B1a result in a higher level of VRN-B1 transcripts and an earlier heading time. We confirmed that the expression of the dominant VRN-1 gene induces transcription of the recessive homoeoalleles, coupled with the reduction of the transcript level of a flowering repressor VRN-2.

Diversification of the duplicated F3h genes in Triticeae.

The F3h gene encodes the flavonoid synthesis enzyme flavanone 3-hydroxylase. Unlike most plant genomes, the bread wheat (Triticum aestivum L.) B genome has two, rather than just one F3h copy. The paralogous F3h-B2 sequence was isolated by PCR and shown to be transcribed, but its predicted polypeptide differed from the typical F3H sequence at a number of the conserved residues associated with its putative substrate-binding sites. The F3h-B2 promoter region was highly divergent from that of F3h-B1, and the transcriptional profiles of the two genes were distinct. Among a panel of 95 Triticeae accessions, representing 24 species, an F3h-2 copy was only detected within those carrying a B, S, G, or an R genome. Analysis of the coding sequence divergence suggested that a small segmental duplication occurred early in the evolution of the Triticeae tribe. The duplicated F3h copy appears to have acquired a novel function in the progenitor of the closely related B, G, and S genomes, as well as in the R genome. In other Triticeae genomes, the F3h-2 paralog may have been lost following pseudogenization.

[Expression of the F3h gene in various wheat organs].

In plants, the F3h gene encodes akey enzyme of flavonoid biosynthesis pathway, flavanone 3-hydroxylase. In most plant species, F3h is a single-copy gene, whereas in the genome of bread wheat (Triticum aestivum L., 2n = 6x = 42, BBAADD), four copies of this gene were found. Using RT-PCR, transcription of these copies was studied in various organs of several wheat genotypes. Three homoeologous copies (F3h-A1, F3h-B1, F3h-D1) manifested similar expression patterns and were specifically transcribed in caryopsis pericarp, culm, coleoptile and leaf colored with anthocyanins. The paralogous copy F3h-B2 in the B-genome was expressed only in wheat roots and probably is involved in biosynthesis of some uncolored flavonoid compounds unrelated to anthocyanin biosynthesis.

[Use of SNP markers developed for allopolyploid wheat].

In this work, we analyzed 54 domestic cultivars of hexaploid (common) wheat Triticum aestivum L. (AABBDD genome) and accessions of tetraploid wheats of the Timopheevi group (AAGG) and rye Secale cereale (RR) using 21 SNP markers for common wheat. It was demonstrated that application of the SNP markers developed and verified for particular common wheat cultivars in allele-specific PCR analysis of other cultivars with different geographic origins could lead to an incorrect estimation of the similarity between the genotypes tested. The studied SNP markers of common wheat are inappropriate for analyzing genomes of other cereal species, in particular, Timopheevi wheats and rye S. cereale.

[Genomic changes at early stages of formation of allopolyploid Aegilops longissima x Triticum urartu].

Using the model of synthetic allopolyploid Aegilops longissima TL05 x Triticum urartu TMU06 of the first generation, the degree and character of changes in subtelomeric, microsatellite and random amplified DNA sequences (RAPD) on early stage of polyploidization was estimated. Study of genome changes was performed by comparing of PCR spectra obtained while amplifying genome DNA of allopolyploid and its parental forms. For analysis of subtelomeric DNA, we used 66 pairs of primers composed of 11 singular primers designed for subtelomere DNA sequences of cereals. RAPD analysis was performed with usage of 38 primers, in microsatellite (SSR) analysis 23 primer pairs were used. RAPD analysis appeared to be a more effective PCR-based method to identify genome changes. Absence of some PCR fragments typical for parental genome in RAPD specters of allopolyploid TL05 x TMU06 was shown using 13 primers of 38 (34%), and with usage of subtelomere primers such changes in PSR specters were shown only for one of 66 pays of primers (1.5%). SSR loci were stable during the polyploidization process. Subsequent analysis of PCR fragments absent in specter of synthetic allopolyploid showed that high level of genome changes in RAPD analysis is probably connected with more effective ability of this method to reveal point mutations. Some data was found suggesting that not all genome changes observed in experimentally synthesized allopolyploids of the first generation are consequences of coadaptation of few genomes in one nucleus.

Single nucleotide polymorphisms in rye (Secale cereale L.): discovery, frequency, and applications for genome mapping and diversity studies.

To elucidate the potential of single nucleotide polymorphism (SNP) markers in rye, a set of 48 barley EST (expressed sequence tag) primer pairs was employed to amplify from DNA prepared from five rye inbred lines. A total of 96 SNPs and 26 indels (insertion-deletions) were defined from the sequences of 14 of the resulting amplicons, giving an estimated frequency of 1 SNP per 58 bp and 1 indel per 214 bp in the rye transcriptome. A mean of 3.4 haplotypes per marker with a mean expected heterozygosity of 0.66 were observed. The nucleotide diversity index (pi) was estimated to be in the range 0.0059-0.0530. To improve assay cost-effectiveness, 12 of the 14 SNPs were converted to a cleaved amplified polymorphic sequence (CAPS) format. The resulting 12 SNP loci mapped to chromosomes 1R, 3R, 4R, 5R, 6R, and 7R, at locations consistent with their known map positions in barley. SNP genotypic data were compared with genomic simple sequence repeat (SSR) and EST-derived SSR genotypic data collected from the same templates. This showed a broad equivalence with respect to genetic diversity between these different data types.

Comparative mapping of genes for glume colouration and pubescence in hexaploid wheat (Triticum aestivum L.).

Microsatellite markers were used to map the major genes Bg (determining black glume colour), Rg1 and Rg3 (red glume), and a locus determining smokey-grey coloured glume to the distal ends of the short arms of the homoeologous group 1 chromosomes, proximally (or closely linked) to Xgwm1223 and distal to Xgwm0033. On this basis, we propose that these genes represent a set of homoeoloci, designated Rg-A1, Rg-B1, and Rg-D1. Rg3 and Bg appear to be variant alleles of Rg-A1. Both Rg3 and Bg are closely linked with the major glume pubescence gene Hg. Similarly, the hexaploid wheat smokey-grey glume gene and Rg2 represent alleles at Rg-D1. The microsatellite markers linked to the Rg genes were used to analyse a phenotypically and genotypically characterized set of Siberian spring wheats. A coincidence between the presence of the 264-bp allele of Xgwm0136 and Rg-A1b (Rg3) was observed; so Xgwm0136 can probably be used as a diagnostic marker for this gene.

[SNP markers: methods of analysis, ways of development, and comparison on an example of common wheat].

SNPs (single nucleotide polymorphisms), which belong to the last-generation molecular markers, occur at high frequencies in both animal and plant genomes. The development of SNP markers allows to automatize and enhance tenfolds the effectiveness of genotype analysis. This review summarizes literature data on methods of SNP polymorphism analysis. Various methods of developing SNP markers are considered, taking common wheat Triticum aestivum L. as an example. These markers are compared to other DNA markers, in order to ensure adequate choice of marker type for solving various molecular genetic problems.

[Analysis of DNA markers specific for G-genome of wheat]. / Analiz DNK-markera, spestifichnogo dlia G-genoma pshenitsy.

A RAPD marker specific for the G genome of wheat was identified. The corresponding 1171-bp DNA sequence was cloned and analyzed. Screening of the database did not reveal any homologies with the known plant DNA sequences. Using the primers specific to the flanking regions of the marker sequence, PCR analysis of the polyploid wheat species and the diploid species of the section Sitopsis was carried out. In addition, using the cloned sequence as a molecular hybridization probe, RFLP analysis of the genomic DNA of these species was performed.

Genetic diversity in cultivated plants-loss or stability?

Human activities like urbanisation, the replacement of traditional agriculture systems by modern industrial methods or the introduction of modern high-yielding varieties may pose a danger to the biological diversity. Using microsatellite markers, we analysed samples of cultivated wheat ( Triticum aestivum L.) collected over an interval of 40-50 years in four comparable geographical regions of Europe and Asia. No significant differences in both the total number of alleles per locus and in the PIC values were detected when the material collected in the repeated collection missions in all four regions were compared. About two-thirds of the alleles were common to both collection periods, while one-third represented collection mission-specific alleles. These findings demonstrate that an allele flow took place during the adaptation of traditional agriculture to modern systems, whereas the level of genetic diversity was not significantly influenced.