CMS systems in rapeseed and their use in the breeding of domestic hybrids

Development of heterotic hybrids is the most efficient approach to solve the problem of increasing the yield of rapeseed (Brassica napus L.), a leading oilseed crop. The cytoplasmic male sterility (CMS), widely used in rapeseed hybrid seed production, makes it possible to control hybridization between female and male lines. A review of publications on the nature of CMS systems in rapeseed and their utilization in breeding is presented. In rapeseed there are more than 10 known CMS systems of alloplasmic and homoplasmic origin. The male sterility character proved to be determined by chimeric mitochondrial genes, characterized by the presence of novel transcribed open reading frames (orf). Mitochondrial CMS genes associated with nap, pol, ogu and Nsa sterility types as well as nuclear Rf genes for pollen fertility restoration were identified. Molecular marker systems for identification of CMS-inducing and male fertility restoring genes were developed. The ogu, pol, MSL and inap CMS systems are commonly used for producing industrial rapeseed hybrids. The State Register of the Russian Federation for 2019 contains rapeseed hybrids of only foreign origin. Main achievements in domestic rapeseed hybrid production are highlighted. Research and breeding institutions developed new source material for rapeseed hete rotic hybrid breeding in various regions of the country. The sterility and fertility restoration sources were received from Canadian and French institutions as well as from domestic working collections. The yield structure traits did not deteriorate after transferring hybrid maternal lines to the sterile cytoplasm, while the glucosinolate content increased when pollen fertility restoring genes were transferred into paternal lines. Dihaploid (androclinium) lines and in vitro culture of unfertilized ovules were used to accelerate the breeding process. Experimental hybrids were developed using pol and ogu CMS

Cytoplasmic male sterility and prospects for its utilization in breeding, genetic studies and seed production of potato

Increasing interest to cytoplasmic male sterility (CMS) and searching for restoration of pollen fertility (Rf) genes in potato is determined by a new way in the modern breeding of this important crop, the development of heterotic hybrids obtained after crosses of inbred diploid lines. The paper reviews the main results of studies on CMS-Rf genetic systems in different species of cultivated plants, the modern methods and approaches of investigating molecular mechanisms of CMS and pollen fertility restoration, and also the available literature data on the status of these studies in potato. The nature of chimeric mitochondrial genes accounting for cytoplasmic male sterility is considered; the peculiarities of the structure and functions of restoration of pollen fertility genes are discussed; examples of CMS-Rf genetic systems in cultivated plant species including representatives of the family Solanaceae are presented. The main results of research on molecular mechanisms of CMS and fertility restoration obtained in the post-genomic era for various plant species using methods of transcriptomic and proteomic analyses are provided. As in many plant species, cytoplasmic male sterility in potato is of hybrid origin. The results of investigating genetic control of male sterility in potato are presented that have been carried out using conventional approaches (hybridological analysis) and led to the formation of the concept of genic cytoplasmic male sterility in some species of section Petota of the genus Solanum. The characteristics of potato cytoplasms types which are associated with male sterility are given. According to classification of Hosaka, Sanetomo (2012), these types include: T/beta, W/gamma and D, each distinguished by the phenotypic appearance of male sterility traits and also by the frequency of occurrence in the breeding varieties gene pool and in various potato species. The results of studies on developing DNA markers for identification of various potato cytoplasm types are presented

Academic stress and its effect on medical students’ mental health status

This review aimed to analyze the data on features of a medical students’ mental status and its dynamics in the course of study. The analysis was applied to the scientific publications (mainly over the past 5 years) on the issue of academic stress and medical students’ mental status in different countries from computer databases: PubMed, Medical-Science, eLibrary, Web of Science, and Scopu

Identification of duplicate accessions in the pea (<i>Pisum sativum</i> L.) collection at VIR

Background. Identification of duplicates in the collections of genetic resources is the most important problem of seed gene bank management. Duplicate accessions expand the collection size, thus raising the costs of germplasm maintenance without broadening the genetic diversity.Materials and methods. The studied material included 17 pairs of Pisum sativum L. accessions from the VIR collection which presumably had been erroneously registered twice in the VIR catalogue; however, they had identical introductory numbers. The accessions entered the collection in 1922–1996 and to date they have been reproduced 2 to 16 times. After a field assessment, 15 pairs of putative duplicate accessions of various uses were selected for molecular analysis. A RAPD analysis was performed using five primers from the Operon Series. Total seed proteins were analyzed by SDS-polyacrylamide gel electrophoresis.Results. The following criteria were used to ascertain identity of the accessions or their difference: 1) similarity of morphological characters (habitus, and anthocyanin pigmentation of flowers and vegetative organs) and flowering dates; 2) identity or polymorphism of RAPD profiles; and 3) identity or difference in electrophoretic banding patterns of seed storage proteins. Seven pairs of duplicates were identified according to the results of a comparative analysis. Among them, the accessions in the pairs k-81/k-1199, k-8331/k-8645, k-8719/k-8760, and k-8757/k-8825 turned out to be completely identical, while k8464/k-8472, k-8740/k-8873, and k-8689/k-8723 were heterogenic, but had similar RAPD profiles and seed proteins patterns.Conclusions. An integrated assessment involving in-field plant phenotyping and analyzing polymorphism of amplified DNA fragments and components in electrophoretic banding patterns of seed proteins is promising for detecting identical or heterogenic accessions in genebank collections

Simulation models in terms of integration of the energy markets

© Medwell Journals, 2017. Study considers to the modeling of wholesale energy markets in the context of implementation of the roadmap. We use a comprehensive simulation model to study the influence of structural factors on the development of national and regional energy. In addition, we evaluate the impact of the generating companies specifically its impact on prices, offers and sales of electric power on the market without a reaction from competitors. The results of the study are discussed in relation to the road map in energy. Our findings are also applicable to wholesale energy markets, the EU and Russia

Juvenile resistance of barleys from the East Asian center of crop origin and domestication to powdery mildew

Background. A significant reduction in the yield of barley may be provoked by powdery mildew (causative agent: Blumeria graminis (DC.) Golovin ex Speer f. sp. hordei Marchal). A vast majority of cultivars approved for use in Russia are susceptible to the pathogen. Including genotypes protected by previously unused resistance genes into breeding practice is necessary to ensure the national food security. Barley landraces could become a fairly rich source of replenishment for the bank of effective pathogen resistance genes.Materials and methods. The study covered 950 barley accessions from the East Asian center of crop origin and domestication: 449 accessions from Japan, 313 from China, 173 from Mongolia, and 15 from Nepal. The experiments were carried out on young plants in a climatic chamber under artificial infection conditions. The northwestern (Pushkin, St. Petersburg) population of B. graminis served as an inoculum. Plant resistance was assessed using a scoring scale. The resistance of the selected forms was assessed twice.Results and conclusions. Significant variability of barley accessions from the countries of East Asia in their resistance to powdery mildew was observed. Symptoms of the disease were not found on plants of 16 studied forms. Weak or moderate development of the B. graminis mycelium was recorded for 21 accessions. Twenty-seven accessions were heterogeneous in the studied trait. Various levels of resistance were identified in 64 studied accessions (6.73%), among which 44 represented cultivars and breeding lines, and 20 were landraces. The percentage of accessions susceptible to the studied population of the pathogen was 93.27%

The effect of equal-channel angular pressing on microstructure, mechanical properties, and biodegradation behavior of magnesium alloyed with silver and gadolinium

The effect of equal channel angular pressing (ECAP) on the microstructure, texture, mechanical properties, and corrosion resistance of the alloys Mg-6.0%Ag and Mg-10.0%Gd was studied. It was shown that ECAP leads to grain refinement of the alloys down to the average grain size of 2–3 μm and 1–2 μm, respectively. In addition, in both alloys the precipitation of fine particles of phases Mg$_{54}$Ag$_{17}$ and Mg$_{5}$Gd with sizes of ~500–600 and ~400–500 nm and a volume fraction of ~9% and ~8.6%, respectively, was observed. In the case of the alloy Mg-6.0%Ag, despite a significant grain refinement, a drop in the strength characteristics and a nearly twofold increase in ductility (up to ~30%) was found. This behavior is associated with the formation of a sharp inclined basal texture. For alloy Mg-10.0%Gd, both ductility and strength were enhanced, which can be associated with the combined effect of significant grain refinement and an increased probability of prismatic and basal glide. ECAP was also shown to cause a substantial rise of the biodegradation rate of both alloys and an increase in pitting corrosion. The latter effect is attributed to an increase in the dislocation density induced by ECAP and the occurrence of micro-galvanic corrosion at the matrix/particle interfaces

POLYMORPHIC VARIANTS OF SUNFLOWER <i> RFL-PPR </i> GENES AS MOLECULAR GENETIC MARKERS

A sample of 131 sunflower lines from VIR genetic collection which differed for the ability to suppression of the CMS phenotype was studied using molecular markers specific for the CMS PET1 associated mitochondrial locus orfH522 and Rf1 nuclear gene, and also for CAPS-markers developed on the bases of single nucleotide polymorphism of RFL-PPR genes homologs. With the use of hybridological analysis a tight linkage of HRG01 and HRG02 marker fragments with the Rf1 gene controlling pollen fertility restoration trait was confirmed. The allelic variants of the RFL-PPR genes sequences were associated with the allelic state of the Rf1 locus. However, the CAPS marker elaborated for the QHL12D20 fragment showed independent inheritance from pollen fertility restoration trait in the F2 of the hybrid VIR116xVIR740

LOCAL BARLEY ACCESSIONS FROM ETHIOPIA RESISTANT TO POWDERY MILDEW

The mlo11 allele associated with the loss of function of the Mlo locus and controlling mildew resistance in the majority of modern barley cultivars was identified in Ethiopian barley landraces. Twenty-seven accessions from Ethiopia were studied during laboratory experiments which resulted in identifying k-5448 as an accession resistant to powdery mildew. Three accessions (k-8555, k-8682 k-17554) were heterogeneous by the studied trait. With the help of molecular markers we showed that the resistant components of the selected forms are protected by the mlo11 gene