Relevance. Interspecific hybridization in the genus Allium L. is the best way to increase biodiversity by introgression of desired traits within the genus. This is valuable for signs such as resistance to diseases and pests, accumulation of important metabolites, obtaining new sources of cytoplasmic male sterility. The creation based on interspecific hybridization of fundamentally new plant forms with unique genetic material makes it possible to expand the selection of genotypes that are valuable in practical terms.Methods. To characterize the breeding material, the plants of interspecific allium hybrids were evaluated using morphological and phytopathological analyses. The analysis of plants of interspecific hybrids of the genus Allium L. from various inbred offspring from BC1-2 combinations of crossing species A. cepa × A. vavilovii and A. cepa × A. fistulosum by breeding characteristics was carried out. Plants were studied by weight, color, bulb shape, number, height of seed stalks, seed productivity and resistance to downy mildew.Results. The biodiversity of plants was revealed: by weight, shape, color of the bulb; by resistance to downy mildew of plants of the first year of vegetation and seed plants; by the number, height of seed stalk; by seed productivity. Plants of interspecific allium hybrids formed bulbs weighing up to 120 g, white, yellow, brown and red, elliptical, broadly elliptical, round and transversely elliptical bulb shape. Phytopathological assessment of allium plants of the first year of vegetation and seed plants revealed diversity in inbred offspring with resistance to peronosporosis. In the combination of crossing species A. cepa × A. vavilovii plants of the first year of vegetation had the largest number of resistant plants to downy mildew (up to 66.7%). According to the seed productivity of plants, depending on the combination of crossing, inbreeding generation and backcross, highly fertile plants with increased seed setability (up to 2.0 g /plant) were identified. The conducted studies have demonstrated an increase in the biodiversity of allium plants obtained based on interspecific hybridization, backcrosses and inbreeding.

One of the most important crops among all types of Alliums is onion, the value of which is determined by the nutritional and medicinal properties. It is used not only as a seasoning for food, but also as a source of a number of biologically active substances. The biochemical composition of the bulbs and its green leaves in different periods of growth and development varies, depending on the variety, environmental conditions and agrotechnical methods of cultivation. Creation on the basis of interspecies hybridization of fundamentally new forms of Allium plants with a unique combination of genetic material allows to expand the possibility of selection of valuable genotypes in practical terms. The study was performed on plants of the inbred progenies I4-5 from BC1-2 bulbous forms of interspecific hybrids of Allium crossing combinations F5(A. cepa xA. vavilovii), F5(A. cepa x A. fistulosum). The biometric assessment was carried out after harvesting and drying the bulbs according to the "test Procedure for distinctiveness, uniformity and stability" according to the main breeding characteristics: the color of the dry cover scales of the bulb, the mass of the bulb, the shape of the bulb. As the standard used plant varieties Odintsovets. The biochemical composition of onion samples was determined by the content of dry matter, monosaccharides, the amount of sugars, ascorbic acid, antioxidants. Based on the biometric assessment of the forms of interspecific hybrids of onions, 5 forms were identified according to the uniformity of such features as the color of dry cover scales and the shape of the bulb weighing 50-60 g, which are a qualitatively new source material for breeding. In determining the biochemical composition of the isolated forms of interspecific hybrids of Alliums on the main breeding grounds found that the plants of these forms of onions indicators of dry matter (15%), monosaccharides (1.15-1.71%), the amount of sugars (11.17%), were at the level of the standard, or exceeded it, but the total content of antioxidants (8.22 mg/g) inferior to the standard.

Selection based on interspecific hybridization of fundamentally new plant forms with a unique combination of genetic material allows expanding the scope of genotypic and phenotypic variability. In this work the comparative analysis of plants of interspecific hybrids of genus Allium L. from various inbred descendants of combinations of crossing of species A. cepa х A. vavilovii and A. cepa х A. fistulosum on selection traits is carried out.Forms were identified: by mass of the bulb more than 100 g; with contrasting coloration of dry cover scales bulbs; by the index of the shape of the bulb; on the resistance to peronosporosis of plants of the first year of vegetation and seed plants; by the number of arrows; height of the arrow; on seed production with a sufficiently high percentage of fertile plants. Plants of interspecific hybrids of onions formed bulbs weighing from 20 to 120 g, with white, golden-yellow, dark golden-yellow, brownish and dark purple color of dry covering scales of a bulb. Plants of interspecific hybrids of onions were flat and round-flat shape of the bulb with the frequency of symptoms ranging from 6.9 to 93.3% and from 11.7 to 93.3%. In a phytopathological evaluation of interspecific hybrids of onions the first year of vegetation identified plants with resistance to downy mildew is from 0 to 4.0 points. Was studied the frequency of occurrence of plants in the progenies weight, colour, bulb type, number, height of the seedstalk, seed productivity and resistance to downy mildew. The increase of genetic diversity in onion plants obtained on the basis of interspecific hybridization, backcrossing and inbreeding is shown.

The paper presents the stages of creating bulbous forms between A. cepa L. and A. Vavilovii Pop. et Vved. through hybridization, in vitro embryo culture, backrossing, inbreeding and cross-breeding. As object of research were considered inbred progeny I1-5   from BC1-2F5  combinations of crossing of A. cepa x A. Vavilovii.  The parent species A. cepa L. of the onion variety Odintsovets was the standard. In plants of the first year of vegetation studied signs: the color of dry scales of the bulb, the weight of the bulb, the index of the bulb shape and the number of leaves. Phytopathological assessment of onion plants for resistance to downy mildew (peronosporosis) was carried out. In the progeny of  interspecies hybrids plants were aligned on the color of the bulb (yellow and brownish). The average weight of the bulb varied from 33.5 to 92.3 g in generations I1-5  from ВС1, and in generations I1-5  from ВС2 it varied from 22.1 to 93.6 g. plants of bulbous forms had a flat bulb (I=0.6-0.7). Only plants from the progeny I3   and I5   from BC2 formed rounded-flat bulbs (I=0,8-0,9). The number of leaves in bulbous plants in the progeny varied on average from 5.3 to 7.1 PCs. The score of peronosporosis was low and medium (0.5-1.0). Was selected form of inbred progenies of I1-5   from BC1-2  with a dense bulb is flat and round-flat shape, which combined a relatively high resistance to downy mildew with a mature bulb is capable of storing.

Wild species of Allium L. genus are not only a harbor of resistance to biotic factors such as pathogens and pests and abiotic factor such as drought, cold and freezing, but also have the biochemical composition differed from cultural species. Crosses between wild and cultured species in Allium genus are usually performed to develop breeding forms with improved content of biochemically valuable compounds. Hybrids F1 obtained from combination Allium сера x Allium nutans, where varieties ‘Stuttgarter Riesen’ and ‘Strigunovskiy’ served as parental forms from A.cepa were studied. Biochemical contents and morphological descriptions of obtained plants were also given in the article. NO3, К+, ascorbic acid, dry matter and total watersoluble antioxidants were analyzed in the plants. Increased content of NO3- was found in accession N13 F1 of A. cepa x A. nutans combination that was higher than in other accessions, including control plants. The accession N15 had a much higher content of Cl- and K+ in leaves than in other accessions. The content of ascorbic acid in all hybrids was 2-3 times less than in control accessions and varied from 15.8 to 28.6 mg%. All hybrid accessions had less dry matter content than in control accessions, achieving 9.3 to 11.7%, in control plants, 12.7. The lowest antioxidant content, 15.3 mg/g (conc. in ascorbic acid units), was found out in accession N3, but the highest antioxidant content 37.3 mg/g (conc. in ascorbic acid units) was in accession N16; it was twice higher than in control plants. The obtained hybrid F1 plants from combination A. cepa x A. nutans can be then selected for their best biochemical composition.

The studies found that in the crosses of S. melongena with wild species, used as a male and female component, the interspecific hybrids have the traits of the generative organs of wild species: the shape and flower size, color, shape and fruit size.

In breeding programs agriculture, interspecies hybridization is an important tool for creating a genetically updated source material in the breeding of varieties. The material consisted of perennial plants of interspecific hybrids of onions BC2(F3-5(A. cepa x A. fistulosum)), BC1(F1-5(A. cepa x A. vavilovii)), F5(A. cepa x A. altaicum) and their inbred offspring. As standard on biometrics and the susceptibility of plants with downy mildew used a variety of onion Odintsovets, as this grade participated in the conduct of the saturating crosses of onion and perennial species A. fistulosum L., A. altaicum Pall. Field experiments were carried out according to the standard technique in conditions of the Moscow region at the experimental base of FSBSI FSVC. Based on the results of the research highlighted in the form of combinations of the cross A. cepa x A. vavilovii and A. cepa x A. fistulosum and A. cepa x A. altaicum interest to breeding in number of leaves, length of leaves, number of seedstalks, the height of the seedstalks, high fertility and relatively high resistance to Peronospora destructor. Forms combination of the cross A. cepa x A. vavilovii was characterized by uniformity the number of seedstalks (5-7 PCs), the height of the seedstalks (96 cm) and resistance to downy mildew (1.0-1.5 score). Forms combination of the cross A. cepa x A. fistulosum stood uniformity by the number of seedstalks (5 PCs), the height of the seedstalks (85-96 cm), resistance to downy mildew (1.0-1.5 score) and a high fertility rate (over 60%). On the basis of the company "regrowth – mass setting of seeds" in each combination of mating types was allocated a separate form, which was distinguished by precocity: BC1(F5(A. cepa x A. vavilovii)) (86 days), BC2(F5(A. cepa x A. fistulosum)) (63 days), I1F5(A. cepa x A. altaicum) (61 days).

One of the way of increasing of genetic variability of onion (Allium cepa L.) is the interspecific hybridization. Development of onion interspecific hybrids consists of the study of initial breeding forms, its heterogeneity, ways of crossing and pollination, overcoming of outbreeding problem, sterility and weak fertility of the hybrids of first and next generations, specifics of hybrid’s seeds development, identification and selection of recombinant forms with breeding valuable traits. The stages of development of the bulbous forms of interspecific hybrids of onion are presented in the article. The study was conducted in the “All-Russian Scientific Research Institute of vegetable breeding and seed production” of the Moscow region. The plants of inbreed progenies I1-5 from BC1-2F5 of bulb forms of interspecific hybrids A. cepa х A. Fistulosum as well as the parental forms were analyzed. The breeding and phytopathological assessment of recombinant forms of onion interspecific hybrids was done for qualitative and quantitative traits and for resistance to downy mildew. Using the individual selection for quality and quantity traits, it was found that the forms, whose traits were not undergo the inbreeding depression because of the higher homozygosity can be used for development of linear initial material for breeding for heterosis. The forms with the inbreeding depression have to be used for crossbreeding. Along with increasing of homozygosity, the new modified genotypes appear because of potential variability and genes recombination. It allows to make the purposive selection of recombinant forms for valuable traits. The selected onion forms from inbreed progenies of I1-5 from BC1-2F5 which have bulbs of flat and well-rounded-flat shape are characterized by high resistance to downy mildew and bulbs with good storage ability. The selection process of the recombinant forms from progenies of onion interspecific hybrids obtained based on repeated inbreeding is shown. Using such techniques as stage-by-stage crossing of A. Cepa L. and A. fistulosum L., embryo culture, polyploidization, backcrossing, inbreeding, selection of recombinant forms, etc., the technology of creation of new initial breeding material of onion was developed.