Interspecific incompatibility in wide hybridization of plants and ways to overcome

Wide hybridization is an important factor of angiosperm speciation and provides an introgression of genes between species. In experimental conditions wide hybridization is used to increase the genetic diversity of cultivated plants. Since the emergence of reproductive barriers is of great importance for speciation, plant capacity for wide crosses is determined by a possibility of overcoming these barriers. The review discusses the main types of incompatibility in wide crossing plants, as well as factors and methodological approaches that contribute to overcoming them. The role of Kr genes, which determine incompatibility between wheat and rye, is one of the examples of prezygotic isolation mechanism. Postzygotic incompatibility may be associated with a highly pronounced genetic and epigenetic variability induced by wide crossings. Early stages of the postzygotic period are crucial for developing hybrid seeds due to embryo’s death, including those associated with uniparental chromosome elimination in hybrid cells and abnormal development of the endosperm. A depression and a lethality of F1 hybrids may be the result of interaction between complementary genes, which cause hybrid necrosis, hybrid chlorosis, and hybrid dwarfness. The causes of hybrid sterility are discussed. Nuclearcytoplasmic interactions are regarded as one of the mechanisms of incompatibility in wide crosses. Reciprocal hybrids and alloplasmic lines are the main models for studying cytoplasm effects and nuclearcytoplasmic interactions. Problems concerning work with their models are emphasized. There are some examples underlining the fact that alloplasmic lines are not a plain combination of nuclear genome and cytoplasm of different species. Development of alloplasmatic lines is connected with structural and functional variability of nuclear and organelle genomes

Problems and possibilities of studying malting quality in barley using molecular genetic approaches

About one-third of the world’s barley crop is used for malt production to meet the needs of the brewing industry. In this regard, the study of the genetic basis of malting quality traits and the breeding of malting barley varieties that are adaptive to their growing conditions are relevant throughout the world, particularly in the Russian Federation, where the cultivation and use of foreign malting varieties of barley prevails. The main parameters of malting quality (artificially germinated and dried barley grains) are malt extract, diastatic power, Kolbach index, viscosity, grain protein, wort β-glucan, free amino nitrogen, and soluble protein content. Most of these components are under the control of quantitative trait loci (QTLs) and are affected by environmental conditions, which complicates their study and precise localization. In addition, the phenotypic assessment of malting quality traits requires elaborate, expensive phenotypic analyses. Currently, there are more than 200 QTLs associated with malting parameters, which were identified using biparental mapping populations. Molecular markers are widely used both for mapping QTL loci responsible for malting quality traits and for performing marker-assisted selection (MAS), which, in combination with conventional breeding, makes it possible to create effective strategies aimed at accelerating the process of obtaining new promising genotypes. Nevertheless, the MAS of malting quality traits faces a series of difficulties, such as the low accuracy of localization of QTLs, their ineffectiveness when transferred to another genetic background, and linkage with undesirable traits, which makes it necessary to validate QTLs and the molecular markers linked to them. This review presents the results of studies that used MAS to improve the malting quality of barley, and it also considers studies that searched for associations between genotype and phenotype, carried out using GWAS (genome-wide association study) approaches based on the latest achievements of high-throughput genotyping (diversity array technology (DArT) and single-nucleotide polymorphism markers (SNPs))

Study of fertility and cytogenetic variability in androgenic plants (R0 and R1) of alloplasmic introgression lines of common wheat

Anther culture is one of the methods to obtain DH lines of wheat. A limitation of this method can be cytogenetic instability in plants R0, leading to a decrease in fertility or sterility. In this study, we have investigated the fertility of R0, the fertility and cytogenetic variability of R1 in alloplasmatic introgression lines of common wheat in order to develop a cytogenetically stable DH lines with introgressions from different species. Lines 311/134, 311/FL, 311/IR with the cytoplasm from H. vulgare were studied. 311/134 carries the wheat-rye 1RS.1BL and wheatwheatgrass 7DL-7Ai translocations; 311/FL has the 1RS.1BL translocation and probably introgressions from A. glaucum; and 311/IR has the wheat-rye 1RS.1BL and wheat-Ae. speltoides T2B/2S#2 translocations. Green seedlings developed in anther culture for all lines. Differences between the lines in the ability for androgenesis and in the level of fertility in R0 and R1 have been revealed. Depressed androgenesis, low fertility and high aneuploidy were observed in 311/IR. It has been proposed that the reason for this is cytogenetic instability in gametes, which is caused by Gc genes located on T2B/2S#2. 63.3 % of 311/134 and 311/FL R1 plants that were grown from low seed-set R0 plants were aneuploids. Fertile R0 regenerant plants were identified that segregated in R1 for fertility and chromosome numbers. It has been demonstrated that DH lines are best developed from highfertility R1 plants with 2n = 42 irrespective of fertility in R0

Alloplasmic recombinant lines (H. vulgare)-T. aestivum with 1RS.1BL translocation: initial genotypes for production of common wheat varieties

Alloplasmic lines are formed when the cytoplasm of one species is replaced by the cytoplasm of another as a result of repeated recurrent crosses of wide hybrids with the paternal genotype. Since the cytoplasm replacement results in new intergenomic interactions between a nucleus and cytoplasm leading to variability of plant characteristics, alloplasmic lines with restored fertility can be an additional source of biodiversity of cultivated plants. Earlier, recombinant alloplasmic lines (H. vulgare)-T. aestivum designated as L-17(1)–L-17(37) were formed from a plant with partially restored fertility of the BC3 generation of barley-wheat hybrid H. vulgare (cv. Nepolegayushchii) × T. aestivum (cv. Saratovskaya 29). This male-sterile hybrid was consistently backcrossed with wheat varieties Mironovskaya 808 (twice) and Saratovskaya 29, and Mironovskaya 808 had a positive impact on the restoration of fertility. This paper presents the results of investigation into a group of recombinant alloplasmic lines (L-17F4), as well as into doubled haploids (DH) lines – alloplasmic DH-17-lines obtained from anther culture of alloplasmic lines (L-17F2). The most productive of these lines were used as initial breeding genotypes. Hybrid form Lutescens 311/00-22 developed from the crossing of the alloplasmic DH(1)-17 line (as maternal genotype) with euplasmic line Com37 (CIMMYT), the source of the 1RS.1BL wheat-rye translocation, proved to be successful for breeding. The presence of the 1RS.1BL translocation in the genome of the Lutescens 311/00-22 form and the L-311(1)–L-311(6) alloplasmic lines isolated from it did not lead to a decrease of fertility or sterility in the plants. This indicates that the chromosome of the 1BS wheat does not carry the gene(s) that determine the restoration of fertility in the studied (H. vulgare)-T. aestivum alloplasmic lines. Alloplasmic lines L-311(1)–L-311(6) showed their advantage in comparison with the standard varieties for resistance to leaf and stem rust, yield, and grain quality. The breeding tests performed at Omsk Agricultural Scientific Center, Agrocomplex “Kurgansemena”, Federal State Unitary Enterprise “Ishimskoe” (Tyumen Region), using alloplasmic lines L-311(5), L-311(4) and L-311(6) resulted in varieties of spring common wheat Sigma, Uralosibirskaya 2 and Ishimskaya 11, respectively

Development and characterization of wheat-rye lines combining T1RS·1BL translocation and 5R(5D) chromosome substitution or T1RS·1BL and T5AS·5RL translocations

As a result of crossing substituted lines Saratovskaya 29 (S29) 5R(5A) and S29 5R(5D) with line L2075 (T1RS·1BL), two homozygous wheat-rye lines were obtained in the F7 generation and identified as T5AS·5RL + T1RS·1BL and 5R(5D) + T1RS·1BL, respectively. The rye chromosomes yare of different origins: 5R originated from spring rye Onohoskaya and 1RS from winter rye Saratovskaya 5. A new Robertsonian translocation was obtained where the 5RL arm was translocated to the short arm of wheat chromosome 5A, resulting in the T5AS·5RL translocation chromosome. Two translocations, T5AS·5RL and T1RS·1BL, and one chromosome substitution, 5R(5D), were identified and confirmed to be compensating on the basis of genomic in situ hybridisation, C-banding and 1RS- and 5R-specific PCR markers. Evaluation of resistance to fungal diseases revealed that homozygous T5AS·5RL + T1RS·1BL and 5R(5D) + T1RS·1BL lines are resistant to leaf rust and powdery mildew

ANDROGENESIS ABILITY IN COMMON WHEAT EUPLASMIC LINES AND ALLOPLASMIC RECOMBINANT LINES (H. VULGARE)-T. AESTIVUM POSSESSING 1RS.1BL AND 7DL-7AI TRANSLOCATIONS AND PRODUCTION OF DOUBLE HAPLOID LINES

Androgenesis ability was studied in anther cultures of euplasmic lines of common wheat and alloplasmic recombinant lines (H. vulgare)-T. aestivum with 1RS.1BL and 7DL-7Ai translocations. The ability to produce androgenic structures and plantlet regeneration are suppressed in lines carrying both translocations. Alloplasmic recombinant lines (H. vulgare)-T. aestivum with 1RS.1BL and 7DL-7Ai translocations, as well as alloplasmic lines with 1RS.1BL translocation, are characterized by increased ability to create androgenic structures, including polyembryos, and plantlet regeneration as compared to euplasmic lines. The inducing reciprocal influence of barley cytoplasm and rye chromosome 1RS on the androgenesis ability of lines (H. vulgare)-T. aestivum with 1RS.1BL and 7DL-7Ai translocations is discussed. Double haploid lines were developed from androgenic plants with spontaneously doubled chromosome numbers and restored fertility. Of the lines carrying the translocations, the most promising with regard to the manifestation of commercially valuable traits and resistance to diseases were selected in order to utilize them in breeding programs

THE HETEROPLASMIC AND HOMOPLASMIC STATES OF MITOCHONDRIAL AND CHLOROPLAST DNA REGIONS IN THE PROGENIES OF WIDE HYBRIDS OF COMMON WHEAT OF DIFFERENT ORIGINS

The states of the 18S/5S mitochondrial (mt) repeat and some chloroplast DNA regions have been studied in alloplasmic lines of common wheat with cytoplasm from barley species Hordeum marinum subsp. gussoneanum Hudson and H. vulgare L., and in progenies of reciprocal hybrids between Triticum aestivum L. and Secale cereale L. The heteroplasmic state of the 18S/5S repeat, which was a result of biparental mtDNA transmission, is observed in rye × wheat hybrids and in their progenies possessing rye cytoplasm. For the first time, the heteroplasmic state of chloroplast DNA associated with heteroplasmy of the 18S/5S mt repeat has been detected in cereals by using alloplasmic wheat lines. It has been found that the transition of mt- and cpDNA heteroplasmy, barley homoplasmy of chloroplast regions to wheat homoplasmy is associated with complete fertility restoration and barley chromosome elimination from the newly developed nuclear genomes of alloplasmic lines