Selection Of Parental Pairs Research Articles

Selection of parental pairs when obtaining F1 hybrids of white cabbage with resistance to the tip burn of the inner leaves

Relevance. During the formation of cabbage heads, under certain conditions, white cabbage is damaged by a burn of the top of the inner leaves of the head, which abroad received the stable name “tip burn”. This disorder is interpreted as a physiological or non-infectious disease, the cause of which is a violation of calcium intake. The disease manifests itself inside the cabbage head, resulting from the interaction of environmental stress factors and the predisposed genotype. The most effective way to combat this disorder is to develop highly tolerant hybrids. This is especially true for the south of Russia, where the stress load on plants is maximum.Purpose of the study – to develop a principle for selecting parental pairs for developing hybrids that are resistant to the tip burn of the inner leaves of a cabbage head, and to identify promising hybrids. Materials and methods. In 2021-2022 in FSBSI "Federal Scientific Rice Centre", in the department of vegetable growing, 45 hybrid combinations obtained on the basis of 10 inbred lines were assessed under field conditions for the trait "burn damage to the inner leaves of the cabbage head." An analysis of the combining ability of lines according to Griffin, and an analysis of the inheritance of the trait according to Heiman were carried out. In 2023, a competitive test of promising hybrids was carried out.Results. In both years of research, 5 lines had negatively stable TCA for burn damage: Ten4270, Yas25p, Bs1f, Agr 82, 270Hn111. SCA of lines is more subject to changes from year to year. The effects of SCA in hybrids due to dominance, epistasis and overdominance in individual combinations significantly influence the manifestation of the trait in the direction of decrease or increase. The principle of selecting parental pairs to develop stable hybrids is based on a combination of lines with a negative SCA value; in some cases, it is permissible to include one line with an average SCA and low SCA. Analysis of genetic parameters according to Heiman confirms the prevalence of non-additive inheritance of the lesion; in unstable forms, the disorder is controlled by dominant polygenes and is highly heritable.

Зоотехния лабораторных песчанок

For the maintenance of laboratory gerbils, which are a valuable test system in preclinical studies, it is necessary to pay attention to such zootechnical parameters as the conditions of their placement, taking into account the parameters of the microclimate, feeding rations appropriate to their needs, as well as options for providing environmental enrichment. An important process in the maintenance of this type of animal is the selection and provision of a suitable enrichment environment in order to reduce their stress and anxiety levels. In order to maintain the number of available gerbils or increase it, it is necessary to take into account their reproductive indicators, as well as species characteristics when composing parental pairs. To carry out a traditional analysis of the scientific literature on the zootechny of laboratory gerbils. The search for publications was performed in the PubMed and Google Scholar databases. The review included searchable publications as of September 11, 2023. In this review, the main aspects of keeping gerbils were identified, namely: optimal floor area, frequency of cell replacement, as well as features of proper animal capture, optimal microclimate conditions (permissible temperature, humidity, ventilation and lighting conditions), types of environmental enrichment, feeding and watering of animals depending on their age and physiological conditions, as well as reproductive indicators of gerbils, including features of the selection of parental pairs. When analyzing the literature data, the main recommendations on the maintenance of gerbils were collected, taking into account all zootechnical needs for their placement and reproduction.

Analysis of the frequency of distribution of CVM, BY BLAD in cattle populations

The modern selection of Holstein cattle is aimed at increasing milk production. However, using sires that are carriers of genetic anomalies contributes to more unwanted recessive alleles in cattle populations, leading to significant economic losses. Both phenotypic and genetic factors influence the performance of herd reproduction. The presence in animal populations of recessive alleles that determine genetic diseases increases the likelihood of the appearance of lethal homozygous genotypes in offspring. Such destructive genetic disorders are called LoF mutations that lead to the malfunction of the genes. The increase in the frequency of occurrence of LoF mutations in the population dictates the need to control their spread. This paper assessed the frequency of carriers of genetically determined diseases in the Ural cattle population. Data were obtained for three recessive disorders: BY - 1.16%, CVM - 1.8, BLAD - 3.79%. According to the literature review, the received data are close in value to the average compared with the results of other studies. This can be explained by the fact that the descendants of outstanding sires bred in the United States are used for breeding in the Urals. Thus, screening of sires and individuals included in pedigree stock, with the further selection of parental pairs, considering the results obtained, is a preferable conservative strategy to prevent the spread of recessive mutations.

Analysis of allelic variants in genes associated with meat productivity in regionalized small cattle breeds

The purpose of the research was to study the polymorphism of allelic variants of genes associated with high meat productivity for further selection of parental pairs using genetic methods. Genotyping of the Dagestan mountain sheep breeds (broodstock and rams) was carried out using a polymerase chain reaction. Genotyping was carried out for the following genes: CAST, GH, GDF9 on a Tertsik thermal cycler. Analysis of the results of PCR carried out with samples of sires of the Dagestan rock breed indicates that the GH gene polymorphism is represented by the A allele, with a high (0.87) and allele B, with a low (0.13) frequency of occurrence. The GDF9 gene polymorphism is represented by the GDF9G allele with a high (0.82) and the GDF9A allele with a low (0.18) frequency of occurrence. The distribution of homozygous genotype GHAA and heterozygous GHAB reached 84% and 16%, respectively. At the same time, the homozygous GHBB* genotype was absent in the studied sample. As a result of the research, new knowledge was obtained on biodiversity and forms of associations of polymorphism of the genes calpastatin, somatotropin, differential growth factor; breed-specific, population-specific features of the allelic spectrum of the CAST, GH, GDF9 genes in sheep of the Dagestan mountain sheep breed were established.

Zein patterns as effective markers of valuable agronomic traits in maize

The effective use of maize (Zea mays L.) in agriculture depends entirely on the knowledge of its gene pool, which, in turn, needs to undergo registration and certification as new data become available. Maize is one of the model objects for applying the marker methodology. This article summarizes the results of a long-term study of the maize gene pool at N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) in two main areas: identification of the world genetic diversity of maize (including the most important wild relatives for breeding use), and search for reliable protein (zein) markers of traits valuable for breeding in order to use them in improvement, seed production, and seed control of this crop. Specific examples show the effectiveness of using zein markers in the development of new inbred lines and improvement of the existing ones. On the examples of such agronomic traits as early maturity, explosiveness, and waxiness of maize grain, the possibility of controlling the “inclusion” of these traits in the breeding material with the help of zein markers has been demonstrated. Evidence of the effectiveness of applying zein markers in the selection of parental pairs to obtain highly heterotic hybrids is presented. The nomenclature of zein adopted at VIR after its separation by polyacrylamide gel electrophoresis (PAGE) in an acidic buffer was compared with the nomenclature of zein after polyacrylamide gel electrophoresis with sodium dodecyl sulfate (SDS-PAGE) adopted among the foreign scientific community. The studies were performed on a large volume of accessions from the VIR collection as well as on breeding material provided by the country’s leading breeders.

Exterior features of American miniature horses of the pony farm "Idalgo"

The main task of preserving populations of small breeds of horses imported from abroad with their unique characteristic features of the exterior and type of constitution is the organization of the reproduction of the livestock and the preservation of the exterior parameters of the breed in descendants. In modern conditions of a small number of populations of such breeds, the influence of the inbreeding depression factor increases, as well as the manifestation of recessive mutations and hereditary pathologies in the offspring.[8] On the one hand, this can form changes that are not typical for the breed: phenotype, measurements, body type of the animal's format; on the other hand, such features of breeding horses in the absence of a selection press and selection will lead to the formation of a population of horses of the breed type. Such breed types should be fixed by breed leaders and have a territorial localization; if this does not happen, then the livestock that does not meet the requirements of the breed may lose the status of purebred. [2][6] The study consisted in monitoring the indicators of measurements by generation to identify the dynamics of changes in the format of the horse population and their compliance with the breed standard of American miniature pony horses. The article presents the indicators of the main measurements of American miniature pony horses for a number of generations and carried out their comparative analysis, with the standard requirements of the corresponding measurements of the breed. The analysis showed the following dynamics: in height at the withers, the increase is 46.5%, in the oblique length of the body, the increase is 97.8%, in the distance from the withers to the tail, the increase was 103.5%, which characterizes a more intensive growth of the peripheral skeleton in the postembryonic period and the formation of an elongated format with age . While the angle of the shoulder, wrist and tarsus is less variable in the age aspect and depends on individual hereditary factors, and not on age. A number of recommendations have been developed for specialists of the club "IDALGO" on the selection of parental pairs for correction for compliance with the standard requirements for measuring indicators in offspring.

Genotypic and phenotypic characteristics of the Western Siberian Hereford cattle population

Breeding and pedigree work aimed at increasing the intensity of growth of young animals and improving herds, ultimately consists in the accumulation of highly productive animals, and in the future - related groups and lines. It is carried out mainly through the use of bulls-improvers, which have passed the two-stage evaluation. The results of the complex characterization of the animals of the Siberian selection of Hereford breed from the breeding farms of the Novosibirsk region are presented. It has been established that in the leading pedigree breeding units the stud bulls of the Maer-Vern 88480, Baldwins Leda 10r, Baz Gold Sol 2v268279, Yarlyk 413 of Siberian reproduction and imported Hellington 88 910 of Finnish selection, Red Note 28 722 279, Kingly 1 Hyrrow 2 976 500 345 and Highflight Wetmore 377 231 of Canadian origin are used in the breeding work with regard to small number of other lines. The productivity limit for the period of economic use in calves ranges from 2.5 to 9.4 lactations, live weight from 507 to 569 kg, milk yield from 189 to 204 kg, height at hips from 125 to 131 cm and the reproduction score from 8.2 to 9.3. On these farms, leader bulls were bred on the basis of heterogeneous and improving selection of parental pairs, which are included in the repair group of stud bulls. The live weight at 15 months is 458-616 kg and corresponds to the class of elite-record. The average daily gain of live weight during the test period from 8 - to 15 months of age is within 1052-1381 g.

Features of growth and development of young cattle of Hereford breed of different origin

Relevance. In recent years, there has been a decrease in the total number of cattle of both meat and dairy production. In this regard, the study of the features of breeding of beef cattle is relevant. In the studies, the growth and development indicators of the young cattle of Hereford breed were studied, depending on their origin.Methods. The research was carried out in the conditions of a breeding reproducer of LLC "Chebomilk", Cheboksary district of the Chuvash Republic. The dynamics of growth and development were studied by monthly weighing of animals. In newborn calves at the age of 205 days, 6, 8, 9 and 12 months, and in heifers additionally at 15 and 18 months, the height in the sacrum was measured. Based on the data from the weighing results, the absolute and average daily increase was calculated.Results. It was found that the growth rate of heifers and calves on fattening is influenced by the genotype of the father. When comparing the average live weight of young animals at the age of 18 months, the best results were in bulls received from the bull Perets — 375.8 ± 17.5 kg, this is 3.8 kg more than the same indicator for bulls received from the bull Timeline and 7.8 kg more than the bull Emuleishn, and by the live weight of heifers at the age of 18 months the Timeline is leading — 352.6 ± 25.2 kg. Bulls and heifers — descendants of the bull Perets of the Mayer-Verne 88480 line are distinguished by the best growth rate. The average daily increase at 18 months of age in bulls was 931 ± 57.2 g, in heifers — 577 ± 54.1 g, which is higher than their peers by 1.2–12.2%. To improve the productive and breeding qualities of the Hereford breed, it is recommended to carry out targeted selection and selection of parental pairs.

Using the dominance coefficient in assessing cotton families

Optimization of the cotton breeding process at the present stage is the main condition for the success of practical breeding. The need for continuous change and improvement of varieties, as well as a reduction in the timing of their breeding, requires a revision of the arsenal of breeding methods and many theoretical attitudes from the point of view of the ideas of modern genetics. The ideas of statistical genetics are especially effective for the development of the theory and methods of selection, as well as its central link - the theory of selection and selection of parental pairs. In practical terms, they make it possible to develop the most accurate criteria for the selection, selection and evaluation of breeding material, and this is the main content of optimization of the breeding process. Even in the strictest self-pollinators, although rarely, the plants are re-pollinated or, in any case, are capable of re-pollinating. Consequently, plants can exchange genetic material, transmit the emerging hereditary changes to each other, and it can be considered as a potential population. This article presents the results of studies to study the possibility of using the dominance coefficient when assessing cotton families. It was shown that phenotypically homogeneous families when crossing show different degrees of manifestation of the studied traits in F1 hybrids.

Theoretical, methodological, and breeding results of the DIAS program in increasing grain production using the example of creation of a soft spring wheat variety - Kazakhstanskaya rannespelaya (origin, characteristics, economic value)

The selection of parental pairs is carried out considering their genealogical trees and the dynamics of the lim factors of the environment, in the creation area, with further hybridization, and subsequent multiple re-sowing of the population. The Kazakhstanskaya rannespelaya variety was created by selection from the F5 hybrid combination of Novosibirskaya 67 × Omskaya 9, the Interdepartmental program DIAS. The breeding record of Novosibirskaya 67 consists of 9 and Omskaya 9 – of 37 varieties, of which 19 are of winter origin. The inheritance of ear productivity, in both varieties, followed the type of complementary epistasis, with incomplete dominance and overdominance, with a large proportion, of recessive genes. In conditions of the Northern Trans-Urals, an early-ripening, yielding line was selected in F5 - Lutescens 1227-8-79, which became the ancestor of the Kazakhstanskaya rannespelaya variety. The variety has successfully passed the State variety testing and is registered in the Qostanay, North Kazakhstan and Kokchetav regions of Kazakhstan, and in the Chelyabinsk region of the Russian Federation, according to the grain quality it is included in the list of strong varieties. In the north of Kazakhstan, Kazakhstanskaya rannespelaya is cultivated on large areas. This variety, as a genetic source, has a good variety-forming ability. With its participation, 6 varieties were created in the Research Institute of the Northern Trans-Urals. Of these, Tyumenskaya 29 and Grenada are registered in 9 and 10 zones of the Russian Federation. It is used in the breeding programs of the Republic of Kazakhstan.

The influence of complex genotypes in the PRL and β-LG genes in Lacon sheep breed on cheese producing

For the first time, an analysis of the distribution of allele variants in the PRL and β-LG genes was conducted on the Russian population of Lakon sheep. The research established the influence of polymorphism in the studied genes on the quantitative and qualitative characteristics of Adyghe cheese. The analysis of data on 248 Lakon sheep showed a positive correlation between β-LGBB and PRLBB – with protein content in milk and better technological qualities for cheese production. The highest fat content in milk was observed in sheep with the β-LGBB genotype (7.14%). The cheese curd from milk of all genotypes was characterized by optimal density and good elasticity. The yield of Adyghe cheese obtained from milk of animals with the genotype PRLBBβ-LGBB was higher compared to the same parameter from milk of sheep with the genotypes PRLAAβ-LGAA, PRLBBβ-LGAA, PRLAAβ-LGBB by 5.5, 4.5, and 3.0%, respectively, and it also had a higher fat content by 3.04, 2.90, and 1.10%, respectively. The practical significance of the obtained data lies in the prospect of selecting carriers of desirable alleles of the PRL and β-LG genes for targeted selection of parental pairs and obtaining a larger number of offspring with homozygous genotypes. Targeted selection will provide a higher proportion of sheep in the herd with better quantitative and qualitative indicators of milk productivity for with better parameters for cheese production. The work was carried out by order of the Ministry of Agriculture of the Russian Federation No. 082-03-2023-213 dated March 07, 2023.

Creation of selected items with high fiber yield and length based on cotton composite hybrids

The wide range of possibilities of using double, complex and double crossing methods in cotton has been studied in selection research. As a result of the use of complex hybridization, valuable traits of varieties of different genetic origin can be collected in a single genotype in a short period of time. Because in the hybrids created on the basis of complex cross-breeding, the variability of quantitative characters is manifested on a large scale, and the possibility of extensive selection appears in these hybrid populations. It is important to use various breeding methods in cotton selection, which are widely used in other agricultural crops. As a result of transgressive variation occurring in composite hybridization in cotton, the increase in the possibility of isolating recombinants, which are the source of new genetic variations, which gives the opportunity to create new varieties with a positive set of valuable economic characters in a short time, has been confirmed in the selection of other crops. In the article, it is stated that the correct selection of parental pairs and the use of composite hybridization method are important for the improvement of fiber yield and fiber length in the creation of new varieties of cotton. In particular, the effectiveness of using T-3377, T-3378, T-3379 varieties, created on the basis of composite hybridization, in achieving positive results in terms of fiber yield and fiber length was highlighted.

The influence of genotype and year conditions on the transgressive variability of stem length in popu-lations of the second generation of soft winter wheat

In 2019–2020, in the conditions of the experimental field of the Bila Tserkva National Agrarian University, populations of F2 hybrids, created by crossing soft winter wheat varieties that differ in the duration of the growing season, were studied. The aim of the work was to establish the degree and frequency of transgressions in the length of the main stem depending on the meteorological conditions of the year and the parental forms selected for hybridization, and to select selectively valuable recombinants for further research. In 2019, in 40 out of 42 F2 populations, only a positive degree of transgression was established in terms of the length of the main stem, from 2.5 % (Myronivsk early/Kolchuga) to 53.8 % (Zolotokolosa/Shchedra nyva). With the use of maternal cytoplasm of early ripening varieties in four populations, all plants exceeded the extreme maximum values of the parents, and with the hybridization of mid-early, mid-ripening, mid-late varieties, 13 such combinations were studied. In the conditions of 2020, positive transgressive recombinants were isolated only in six out of 20 populations based on hybridization with the maternal form of early-ripening varieties, and negative ones – in nine. Negative transgressive recombinants were selected in 13 of 21 populations created by crossing mid-early, mid-maturing, mid-late varieties. At the same time, no positive transgressions were found. The selection of parental pairs differing in precociousness before hybridization expands morphogenesis in F2 populations of soft winter wheat and promotes the selection of both positive and negative transgressive recombinants by the length of the main stem. A significant influence of meteorological conditions and initial forms of hybridization on the formation of stem length and the manifestation of extreme maximum and minimum values in populations of the second generation of soft winter wheat was established. The use of early-ripening cytoplasm in hybridization has a greater effect on the positive transgressive variability of the length of the main stem in F2 populations compared to medium-early, medium-maturing and medium-late maternal forms. Key words: degree and frequency of transgressions, soft winter wheat, maturity groups, parent forms, main stem length, F2 populations.

The study of breeding material of winter bread wheat according to the main criteria of quality

The study of grain quality at all stages of a variety development, starting with the selection of parental pairs, is the most important condition for the efficiency of breeding. The purpose of the current paper was to estimate winter wheat samples according to the main criteria of grain quality and to select promising ones for further use in the breeding process. The study was carried out in 2019–2021. There were studied new varieties and promising lines of winter bread wheat from the main Competitive Variety Testing, according to green manure fallow. Criteria characterizing grain quality were determined in the laboratory conditions in accordance with methodology and GOSTs. Based on the conducted study, there were identified sources that were characterized by a high severity of grain quality traits. According to ‘grain unit’, there were distinguished such varieties as ‘Matritsa’, ‘Rubin Dona’ and the lines ‘1043/17’ and ‘1582/166’. According to the general kernel hardness there were identified such samples as ‘Matritsa’, ‘Priazovie’ and the line ‘1582/16’. The samples and lines ‘Ermak’, ‘Razdolie’, ‘Rubin Dona’, ‘Matritsa’, ‘Priazovie’, ‘1582/16’, ‘1043/17’, ‘1295/18’, ‘1431/18’, ‘1463/18’, ‘1518/18’, ‘1612/18’ and ‘1895/18’ corresponded to good quality according to SDS-sedimentation. The sample ‘1463/18’ was characterized by a high protein percentage in grain (15.02 %). There were also studied a quantity and quality of gluten, falling number and baking properties. The varieties ‘Rubin Dona’, ‘Matritsa’, ‘Priazovie’ and the lines ‘1582/16’, ‘1463/18’ were characterized by the best expression of the studied traits of quality. These genotypes can be used in the breeding process as sources of high protein and gluten percentage in grain and good baking properties.

Comparative analysis of the results of BLUP-evaluation of sires of diffirent countries origin by the conformation of their daughters

In breeding work one of the priority areas is the improvement of the genetic potential of animals, the effectiveness of which depends on the accuracy of determination and prediction. The method of constructing, optimizing and solving the equations of mixed models for predicting the breeding value of animals is becoming increasingly important, which is based on the principle of maximizing the relationship between sires evaluations based on the characteristics under consideration (BLUP method). One of the important economic indicators in cattle breeding concerning the increase in productivity and the term of their economic use of animals, is the evaluation of sires by the type of conformation of daughters, based on the calculation of breeding value indices. The researches on monitoring and comparative analysis of changes in the genetic value of breeding bulls by the conformation features of off spring at the population level of Black-and-White cattle in the Moscow region have been presented in the article. Groups were formed in the context of the sires’ origin according to countries. The formation of a database on the indicators of the conformation of first-calf heifers has been carried out on the basis of the analysis of materials from the regional information and breeding center of breeding livestock in the Moscow region Mospleminform. In a comparative aspect, evaluations of the breeding value of sires of Russian origin were taken with sires were born in the Netherlands, Germany, Denmark, Canada and the USA. The results of the research have shown that the main emphasis of the breeding of bulls of Russian origin was aimed at strengthening the body traits. The data of the comparative analysis of the variability of the genetic value of sires by the type of conformation of daughters carried out according to the BLUP procedure provide an opportunity to monitor and analyze the direction of breeding work when organizing the selection of parental pairs.

Degree and nature of heterosis effects in corn lines by grain quality parameters

Aim. Widespread use of corn hybrids, which are of key importance for the food security in Ukraine, is one of the most successful examples of the heterosis phenomenon use. In order to recommend new and high-quality corn hybrids for production, it is necessary to assess the inheritance degree and heterosis effects for protein, starch and oil contents as well as for yield. Results and Discussion. To achieve the goal, we used the classic field techniques and methods of qualification examination of plant varieties for suitability for distribution in Ukraine. The protein, starch and oil contents in grain were determined on a InfratecTM 1241 Grain Analyzer (FOSS); the heterosis effects were calculated by D. S. Omarov’s methods. As a result of tester crosses, 65 experimental corn hybrids were obtained. Inbred lines VK13, VK69, AE801 and AE392 (carriers of the wx and ae mutations of endosperm structure, respectively) were the female forms. Inbred lines СО255, АК159, АК157, G255, FV243 and KhLG1203 were used as male components for the first time to obtain hybrids with high grain quality parameters. From the 2020−2021 studies, we found that, in terms of grain quality, the grain starch content-driven selection of parental pairs was the most rational approach, as the influence of parental forms on this trait consistently exceeded 50% across the study years. Conclusion. Hybrids VK13×UKhK678 and VK13×UKhK686 were noticeable for consistently high manifestation the heterosis effects for several parameters. As to the starch content in grain, superdominance of a parental form with stronger expression of the trait was recorded in hybrids VK13×UKhK678, VK13×UKhK686, VK19×FV243, and AE801×VK32; as to the oil content in grain, VК13×UKhК678, VК13×UKhК686, VК13×VК37, АЕ392×СО255, АЕ392×KhLG1203, and АЕ392×АК157 were distinguished. Inbred corn lines that should be used as parents of heterotic corn hybrids (KhLG1203, CO255, AK159 and AK157) were singled out.

Digitalization of the breeding process of clonal apple rootstocks

The paper shows the results of many years of experience in breeding low-growing clonal apple rootstocks at Michurinsky State Agrarian University. The relevance of the introduction of digital technologies at all stages of the breeding process from the formation of a data bank for the selection of parental pairs to research in the garden of the competitive study of rootstock-varietal combinations is shown. The apparatus and software for specific research stages are proposed. It is found that the developed methodology and digital technologies make it possible to significantly reduce the time of the breeding process, achieve the intended results faster and more efficiently and most fully reveal the genetic potential of breeding achievements.

Influence of methods of selection of parents by the index of similarity of antigens in blood groups on weight and linear growth of bulls

In solving the problem of qualitative improvement of meat breeds, an important place is occupied by the improvement of methods of practical use of existing methods of selection of parental pairs using histocompatibility antigens, polymorphic proteins and blood group systems. The purpose of the work is to determine the effect of homogeneous and heterogeneous selection of parental pairs by blood group factors on the weight and linear growth of Ukrainian beef bulls. Ukrainian meat breed is bred using four breeds and is characterised by high variability in polymorphic traits. The type of selection of parents was determined by the index of antigenic similarity (ras) of antigens of the B blood group system of cattle. To calculate the index of antigenic similarity of parents, the formula of D.A. Zhivotovskiy and A.M. Mashurov was used. The selection was considered homogeneous if the parents’ ras ≥ 0.268, and heterogeneous if ras ≤ 0.267. It is proved that bulls that come from parents with higher ras prevail in the test by average daily gain and have a higher live weight. For ras in parents over 0.268, animals tend to improve growth rate by 8 months of age. This trend continues after weaning. Bulls sired by parents with ras up to 0.267 have better average daily gains in the period from 15 to 18 months, which indicates their lower precocity. According to the index of antigenic similarity of parents over 0.268, animals are better in terms of meat forms at the age of 15 and 18 months. At 15 months of age, bulls obtained from homogeneous selection for ras have smaller height measurements, the better developed front part of the body in terms of chest width and depth, and longer torso and hindquarters. Homogeneous selection of parental pairs according to the index of similarity of antigens of the B blood group system improves the weight growth and expressiveness of meat forms in bulls of the Ukrainian beef breed

An effective type of merino in the Volga region by the method of intrabreed selection

The article presents experimental data on the use of intrabreed selection in order to create the most effective productive type of sheep of the Stavropol fine-wool breed. In the zone of the dry steppe of the Volga region the sheep of the Stavropol breed were improved by the meat merino of the Australian selection. Scientific and experimental research was carried out in JSC “New Life” ofNovouzensky district of the Saratov region. The crossbreeds obtained during the step-by-step crossing of Stavropol sheep with tup-producers of Australian meat merino with 1/8-blood content according to AMM by eye-measuring the degree of severity of wool and meat productivity were distributed according to productive indicators (live weight, wool shearing) to the corresponding specific types of productivity. The first group — the uterus of the wool productive type; the second — wool-meat, the third — meat-wool. Each group of sheep was assigned to tuh of meat-wool productive type. The offspring were obtained according to the selection of parental pairs: father x mother. At birth, the M-W x M-W ewe hoggs had an advantage over the W x M-Wanimals in terms of live weight by 7.47%, and over the M-W x M-W — by 1.7%. After weaning at 4.5 months, the live weight of all young animals decreased slightly. In 13.5 months, the superiority of group III over group I and II was 9.3%, 4.6%. In terms of cutting physical wool, group II yarks outperformed group I and III by 1.91 and 3.45%, while their advantage in pure wool was 13.6 and 4.11%. The longest coat was characterized by the young animals of group I, the stronger coat was in the young animals of group III. In the structure of fine-wooled sheep of the Stavropol breed of the Volga population three productive types were distinguished, which differ from each other in terms of productive indicators: wool, wool-meat and meat-wool. At the same time sheep of the Stavropol breed, bred in the dry steppe of the Volga region, to a greater extent deviate towards the wool-meat productive type, such merinos of the combined direction in the conditions of the modern economic situation are most demanded and profitable.

Study of the hybridization of tomatoes for productivity and quality in the conditions of absheron of Azerbaijan Republic

The article discusses the importance of the role of biological diversity of plants, including the problem of specific disappearing tomato varieties which are currently under threat of extinction due to environmental degradation and progress in science and technology, the importance of using them as a source material in breeding work in the aspect of adaptation to local environmental conditions, as well as the importance of preserving, restoring these materials, and obtaining clean lines from them. In the course of the study, several interline F 1 hybrids were obtained from pure lines obtained from local and foreign tomato varieties. The article also reports on the results of studying the combining ability of pure lines used in the selection of parental pairs, giving high productivity and high-quality yield. Combining pure lines with a high combinative ability, we obtained F 1 hybrids with the effect of heterosis, adapted to local ground conditions. Our work also presents data on the restoration of seeds of high-yielding, high-quality tomato varieties of the Scientific Research Institute of Vegetable Breeding. which are stored in the Gene bank of the Institute of Genetic Resources of the National Academy of Sciences of Azerbaijan. In the presented article, in addition to the above, the general and distinctive aspects of modern scientific hypotheses about methods and techniques for creating F 1 hybrids with the effect of heterosis are discussed, depending on the genetic origin of the variety of plant and the influence of local agroecological factors.