The most widespread and harmful disease of barley is net form of net blotch caused by the ascomycete Pyrenophora teres f. teres Drechsler (Ptt). A cost effective and environmentally sustainable strategy for barley protection against Ptt is to develop barley cultivars possessing genetic resistance. In previous GWA analysis, we identified SNP-markers associated with a resistance locus on chromosome 3H in the interval of 45.82–54.53 cM. These SNPs have been described previously in the literature to be located within the same region of chromosome 3H. The aim of the study was to validate QTL markers controlling resistance to Ptt on chromosome 3H in this region by KASP genotyping in four F₂ populations of crosses between the resistant cultivars, Morex, Fox, and Zolo, and the accession, Local k-21578, with the susceptible barley cv. Gesine and in a doubled haploid (DH) population of Canadian Lake Shore (CLS)/Harrington. Eleven of fifteen studied markers showed high efficacy (97.5–100%) for co-segregation with resistance to Ptt in the DH population, CLS/Harrington. Three of these markers located at 54.53 cM and one at 51.27 cM were effective in two F₂ populations of crosses of Morex and Fox with susceptible cv. Gesine. These markers are also located close to each other on the physical map (442,203,921–443,119,491 bp). Apparently, in cultivars, CLS, Morex, and Fox, resistance to Ptt is determined by the same locus. Markers JHI-Hv50k-2016-166392 (47.1 cM, 112,536,071 bp), Clone ID 3255462_1 (51.63 cM, 363,531,898 bp), and Clone ID 3255462_2 (51.63 cM, 363,531,871 bp) showed high efficacy in the DH population and in the F₂ population, Local k-21578/Gesine. Apparently, at least two loci controlling Ptt resistance exist in the chromosome region of 47.0–54.3 cM: one at 46.0–48.44 cM and another at 51.27–54.8 cM. These regions were found to harbor several genes involved in important plant functions, including disease response and signaling pathways. Allele-specific PCR markers were developed based on the KASP assay data and tested on six resistant, two moderately resistant, and two susceptible barley genotypes. Four markers were found to be effective to differentiate susceptible and resistant barley genotypes. The KASP and allele-specific PCR markers associated with Ptt resistance on chromosome 3H will be useful for pyramiding resistance QTLs in barley marker-assisted selection.

NGS-секвенирование в селекционно-генетических исследованиях ячменя

Genome-wide association studies (GWAS) are among the genetic tools for the mining of genomic loci associated with useful agronomic traits. The study enabled us to find new genetic markers associated with grain yield as well as quality. The sample under study consisted of spring wheat cultivars developed in different decades of the last century. A panel of 186 accessions was evaluated at VIR’s experiment station in Pushkin across a 3-year period of field trials. In total, 24 SNPs associated with six productivity characteristics were revealed. Along with detecting significant markers for each year of the field study, meta-analyses were conducted. Loci associated with useful yield-related agronomic characteristics were detected on chromosomes 4A, 5A, 6A, 6B, and 7B. In addition to previously described regions, novel loci associated with grain yield and quality were identified during the study. We presume that the utilization of contrast cultivars which originated in different breeding periods allowed us to identify new markers associated with useful agronomic characteristics.

Barley (Hordeum vulgare L.) is one of the most commonly cultivated cereals worldwide. Its local varieties can represent a valuable source of unique genetic variants useful for crop improvement. The aim of this study was to reveal loci contributing to spike productivity traits in Siberian spring barley and to develop diagnostic DNA markers for marker-assisted breeding programs. For this purpose we conducted a genome-wide association study using a panel of 94 barley varieties. In total, 64 SNPs significantly associated with productivity traits were revealed. Twenty-three SNP markers were validated by genotyping in an independent sample set using competitive allele-specific PCR (KASP). Finally, fourteen markers associated with spike productivity traits on chromosomes 2H, 4H and 5H can be suggested for use in breeding programs.

Peach (Prunus persica (L.) Batsch) is one of the main agricultural stone fruit crops of the family Rosaceae. Modern breeding is aimed at improving the quality of the fruit, extending the period of its production, increasing its resistance to unfavorable environmental conditions and reducing the total cost of production of cultivated varieties. However, peach breeding is an extremely long process: it takes 10–15 years from hybridization of the parental forms to obtaining fruit-bearing trees. Research into peach varieties as donors of desirable traits began in the 1980s. The first version of the peach genome was presented in 2013, and its appearance contributed to the identification and localization of loci, followed by the identification of candidate genes that control the desired trait. The development of NGS has accelerated the development of methods based on the use of diagnostic DNA markers. Approaches that allow accelerating classical breeding processes include marker-oriented selection (MOS) and genomic selection. In order to develop DNA markers associated with the traits under investigation, it is necessary to carry out preliminary mapping of loci controlling economically desirable traits and to develop linkage maps. SNP-chip approaches and genotyping by sequencing (GBS) methods are being developed. In recent years, genome-wide association analysis (GWAS) has been actively used to identify genomic loci associated with economically important traits, which requires screening of large samples of varieties for hundreds and thousands of SNPs. Study on the pangenome has shown the need to analyze a larger number of samples, since there is still not enough data to identify polymorphic regions of the genome. The aim of this review was to systematize and summarize the major advances in peach genomic research over the last 40 years: linkage and physical map construction, development of different molecular markers, full genome sequencing for peach, and existing methods for genome-wide association studies with high-density SNP markers. This review provides a theoretical basis for future GWAS analysis in order to identify high-performance markers of economically valuable traits for peach and to develop genomic selection of this crop.

Climate change, growing world population and increasing food demand require higher yields and adaptability of crops, including spring bread wheat. Modern plant breeding based on achievements of genetics has a significant impact on plant resistance to diseases, climate variability and other factors. Genome wide association studies (GWAS) is one of genetics tools for mining of genome loci associated with economically important traits. In the current study, we applied GWAS to reveal QTL for spike productivity and grain quality using a panel of spring varieties of Triticum aestivum L. bred in different decades of the last century in Russia and Germany. The study has enabled to find new genetic markers associated with grain yield and quality. Studying genetic basis of grain yield and quality by comparison of wheat varieties from different breeding periods, including landraces preserved as the source of valuable genetic diversity for breeding and genetic studies, makes it possible not only to understand selection processes in the past, but also to develop strategies for future breeding work.