Barley is an ancient grain culture, which was cultivated for more than 10000 years (Riaz et al. 2021). During the last 5000 years, humankind naturally cultivated grain. Var-ious kinds and lines were acquired during random muta-tions as well as hybrids (von Vettstein 1995; Chornobrov et al. 2022). This millennial selection influenced major mor-phological changes and quantity of harvest but decreased the amount of genetic variation for further selection (Feuillet et al. 2008; Shahini et al. 2023). Kazakhstan is one of the biggest manufacturers and exporters of food in the world. As such, according to the Food and Agriculture Organization (2021), the overall volume of produced cereals in Kazakhstan as of the year 2021 was over 16.566 million tons (Fig. 1).

Figure 1. Total production of cereals in Kazakhstan, 1961-2021. Source: Food and Agriculture Organization (2021).

Barley is a strategically important crop for Kazakhstan. It gains stable harvests in specific agroclimatic conditions, such as soil salinity, frequent droughts, strong winds, and light frosts in early spring (Tokhetova et al. 2021; Egamberdieva et al. 2022). Currently, Kazakhstan produces around 1.6% of barley in the world (Food and Agriculture Organization 2022). In the region, this grain culture is usually used as fodder to feed livestock and poultry (Almerekova et al. 2019; USDA 2022). As such, it is a priority task for Kazakhstan selections to improve the quality of the seed, mainly focusing on protein quantity. This process is con-trolled by a complex genetic system. The amount of protein in the barley grain greatly depends on a genotype of a crop and environmental conditions. This creates a demand for a discovery of a genotype with lesser mutability in various environments (Cai et al. 2013; Zaiets et al. 2022). High amounts of protein were found in crops, which had favor-able weather conditions during the vege-tative period, while excessive humidity and low temperature during the ripening of grain decreases the quality of grain (Tanchyk et al. 2022). The amplitude of protein mutability in various breeds of barley of different ecological-geo-graphical origination varies from 7.9% to 24.7% (Fatullayev 2019; Panfilova et al. 2019), while barley, harvested in Kazakhstan, contains from 13.5% to 20.3% of protein (Baydyusen et al. 2021).

Literature indicates, that in the field of research, inter-specific hybridization is the most used method in the traditional selection of barley. Simple pairs, complex, and reversal crossbreeding methods are used (Bogdanova and Novikova 2022). According to G.B. Akhmedova et al. (2021), top cross methodology indicates, that Arna, Lignee, Harmal, and Saule varieties have high combinational stability and are deemed reliable donors for the selection of stock fodder feeding cultures. Other parental forms with high yields of protein per grain are bare-grained forms of barley from ICARDA collective material (International Center for Agricultural Research in the Dry Areas): ICARDA-29, ICARDA-52, ICARDA-67 (Tokhetova et al. 2021).

Even though the traditional methodology of barley selections prevails, the literature includes data on the usage of modern fodder grain crop quality improvement methods. For example, genetical analysis (QTL [Quantitative Trait Loci] mapping and GWAS [genome-wide association studies] research with sequencing approach), identifies molecular markers, genome, and new gene regions, that influence various barley characteristics (Langridge 2005; Ceccarelli et al. 2008; Alqudah et al. 2020; Jayakodi et al. 2020; Riaz et al. 2021; Matres et al. 2021) as well as SNP (Single Nucleotide Polymorphism) and GWAS haplotype- based marker technology (Bogdanova and Novikova 2022).

As such, Chinese scientists (Cai et al. 2013) have revealed new HvNAM-1, HvNAM-2, SNP haplotypes, and DArT (Diversity Arrays Technology) markers, asso-ciated with the amount of protein per grain. This data allows us to identify various loci, that influence the protein concentration and to use them in acquiring necessary parental forms. Scientists of Scandinavia also research the influence of HvNAM alleles on protein per grain concen-tration (Hagenblad et al. 2022). It is necessary to note, that modern selection methods for improving fodder grain quality are still in the stage of development and partial implementation into hybridization programs. Hence cur-rently, literature and information sources of selective methods of donor search to acquire high-protein variety and hybrid of barley are fragmental.

The research aims to analyze the origin of barley collective material from diverse ecological-geographical sources and identify potential donors for the development of new varieties and hybrids of improved fodder grain barley. The potential gap of this work seeks to fill is the identification and recommendation of specific barley varieties and hybrids with desirable traits, including protein content and other quality attributes, for inclusion in hybridization programs in Kazakhstan, specifically in the Kyzylorda region. The significance of this study lies in its potential contributions to the development of improved fodder grain barley varieties and hybrids. By analyzing the origin of barley collective material from diverse ecological- geographical sources, the study can identify suitable donor plants that possess desirable traits for the creation of new varieties.

The basis of crop selection is genetic variety, which, under specific conditions, can improve the productivity of agricultural cultures. While barley has three gene pools, only his ancestor (H. vulgare ssp. Spontaneum) and bulbous barley (H. Bulbosum) may be used for recombination with cultivatable barley (H. vulgare ssp. vulgare). Hordeum kind includes more than 30 types, yet other types of wild barley have reproductive barriers and, thus, are not suitable for hybridization.

The methodology for processing collective material in barley research and selection programs involves several stages. Firstly, the collected samples undergo laboratory analysis, where genetic and biochemical traits are assessed. This includes examining protein content, genetic markers, disease resistance, and nutritional composition. Following the laboratory analysis, the selected samples are evaluated in field conditions representative of the target environment (Kyzylorda region). The samples are assessed for their performance and adaptability, considering factors like growth rate, yield potential, drought resistance, and pest resistance. Dedicated sources, including existing cultivars and landraces, are utilized in the selection programs to incorporate desirable traits into the breeding process. The aim is to create new barley varieties and hybrids with improved characteristics, such as grain quality, productivity, and resilience to environmental stresses. Additionally, the methodology focuses on improving local selection kinds, ensuring that local landraces and varieties are optimized for the specific ecological conditions of the Kyzylorda region.

Currently, for selection procedures, worldwide databases have been created, which store genotype and phenotype information of various barley samples. For example, the BarleyCAP Database offers access to genetic markers, genomic sequences, trait data, and pedigrees of diverse barley accessions, aiding in the exploration of genetic diversity. BarleyBase focuses on genomic and expression data, providing researchers with microarray and RNA-Seq data to study gene expression patterns and genetic variations. The Hordeum Germplasm Database houses information on genetic markers, passport data, and phe-notypic data, assisting in the identification of suitable germplasm resources for breeding programs. The Hordeum Toolbox integrates diverse genomic and genetic data, including genetic markers, genetic maps, and phenotypic data, supporting the study of trait genetics and the selection of desirable parental lines.

Kyzylorda region is geographically located in extreme agroclimatic environments, unfavorable for the farming of crops, especially grain and wheat (Fig. 2). With the decrease of Syr Darya river water resources, a specific risk of stable water supply for field irrigation arises, which causes gradual desertification, salinity, and degradation of soil. The climate of the research region is harsh continental with major diurnal and seasonal temperature changes. Summer in the region of research is long, dry, and hot while winter is short and cold. The average temperature per year is 9.8℃, and precipitation – is 129 mm. In the dry period, the level of precipitation is around 40-70 mm, most of which (60%) occurs during the winter-spring period (Karabayev et al. 2011). The research was conducted on test fields of scientific production station of limited liability partnership “Kazakh Research Institute of Rice Growing named after I. Zhakhaev”. Test field soil is meadow-swamp, percentage of humus is 1%. The soil is slightly porous with a relatively high level of thick residue (0.6-0.8%). Soil salinity is average, of sulfate-chloride type. The object of the research were 150 varieties of barley of various ecological-geo-graphical origination.

Figure 2. A geographical map of Kyzylorda region.

High protein and starch samples of barley, which will keep their normal vital functions and ability to accumulate all required reserve elements proportionally, are of high importance for the selection of fodder grain. Due to the analysis being concluded in extreme agroclimatic con-ditions, high-protein parental form selections were con-ducted with a method, that had the following formula for protein per grain, that uses protein factor: “% of starch/% of protein”. Only grains with a factor of 3.5 were deemed of the full value (Akhmedova et al. 2021).

Quality contents of grain were analyzed at the Kazakh Research Institute of Agriculture and Plant (KazNIIZiR). The content of protein per grain was evaluated by the Kjeldahl methodology, while starch per grain was eval-uated by the polarimetry method. It involves the digestion of a sample with concentrated sulfuric acid, which converts nitrogen present in proteins into ammonium sulfate. The resulting ammonium sulfate is then quantified by titration, and protein content is calculated based on the nitrogen content of the sample. The Kjeldahl method is known for its accuracy and has been widely used for protein determination in various food and agricultural products.

Combination ability was evaluated in the system of top crossbreeding with the use of the source-tester attribute. For the analysis of combinative capability, V.K. Savchenko (1981) method was used, while the combinative mutability was evaluated under the influence of environment with L.A. Tarutina and L.V. Khotyleva (1973) methods.

The research considered the ecological features of Kazakhstan when selecting barley varieties by evaluating their performance and adaptability to the specific environ-mental conditions in the country. This involved assessing traits such as stress tolerance, disease and pest resistance, and yield potential. The researchers took into account the diverse climatic zones, soil types, and local agronomic practices in Kazakhstan to identify varieties that could thrive in the country’s challenging ecological conditions. By prioritizing traits that enhance adaptability and pro-ductivity in Kazakhstan’s unique environment, the research aimed to select barley varieties that are well-suited to the ecological features of the country.

During the years 2019-2021, 150 varieties of different ecological-geographical origination were included in the analyzed collection of fodder grain barley (Fig. 3). The big-gest amount of selection material comes from Kazakhstan (KazNIIZiR), with 79 samples. The second place is in the ICARDA collection of samples (Syria), 26 samples. From the collection of CIMMYT (International Maize and Wheat Improvement Center) 18 were taken. Number of seeds from Russia – 13 samples, Ukrainian seeds – 7 samples. The rest of the material comes from Germany, France, Latvia, and Afghanistan. It is important to note, that the amount of protein per grain was different, de-pending on the origination of genotype. The most suitable conditions for the treatment of fodder grain barley in agroclimatic con-ditions of the Kyzylorda region of Kazakhstan are varieties from KazNIIZiR and ICARDA (Syria) collections. Sam-ples from collective materials from countries with a mild climate (Ukraine, Germany, France, etc.) were most suitable for the selection of beer brewing kinds and only one sample from Ukraine (St Sample) can be deemed as a most perspective to develop high-protein kind of barley.

Figure 3. Correlation of analyzed varieties in ecological- geographical origination collection of barley.

A selection of parental forms according to the amount of protein per grain has been followed by the decrease of starch per grain, which influenced the nutritional value of fodder grain barley. Hence, for the creation of high-quality grain varieties and hybrids, parental forms with protein factors 3.5 and more were selected. As a result of the conducted research, varieties with high productivity and increased amount of protein per grain, as well as with the least variability of analyzed characteristics per year were acquired (Table 1).

Table 1 . Varieties of various ecological-geographical origination with higher protein content coefficient and least varia-bility in years 2019-2021.

Variety	Ecological-geographical origination	Starch content, %	Protein content, %	Protein content coefficient	Yielding capacity, g/m2	Weight of 1000 grains, gr.
Arna	Kazakhstan	53.9	12.6	4.3	311.2	43.6
Asem	Kazakhstan	55.3	11.7	4.7	250.4	46.8
Kaiser	Kazakhstan	52.8	12.8	4.1	329.1	41.9
Saule	Kazakhstan	56.0	12.1	4.6	260.0	36.2
Symbat	Kazakhstan	54.0	13.0	4.2	287.9	45.1
Syr Aryi	Kazakhstan	53.5	14.1	3.8	322.3	42.0
13/02-9К	Kazakhstan	53.7	12.2	4.4	327.9	44.4
3/95-14	Kazakhstan	55.0	14.3	3.8	328.5	41.7
99/99-2	Kazakhstan	54.1	14.8	3.7	333.7	34.5
99/99-7	Kazakhstan	52.9	12.5	4.2	330.0	43.3
99/99-8	Kazakhstan	55.6	14.5	3.8	331.6	39.9
Harmal	Syria	54.0	15.0	3.6	442.2	40.2
Lignee-527	Syria	54.2	13.8	3.9	295.8	33.7
Rihane-03	Syria	53.8	13.0	4.1	561.3	43.3
St Sample	Ukraine	57.2	13.6	4.2	554.5	41.0

During the evaluation of source selection material for the amounts of protein per grain in barley the prevalence of protein in varieties with a short vegetative period was established, unlike the medium-late samples. For example, the average factor of protein per grain of Syr Aryi sample (KazNIIZiR) was 14.1%, which is 2.2% higher, than the Russian Obskoy sample (medium-late kind). Unsubstantial variations in analyzed characteristics per year and a correlation coefficient (r) of 0.3 were noted. Perspective source material for high-protein variants and hybrids were varieties of Syrian origin: Harmal and Lignee-527, as well as Ukrainian variety St Sample. They had a high intensity of germination in salinity solution and showed resistance to root rot, while St Sample showed resistance to covered smut. From the results of research, it is clear, that more dry conditions slowed the growth of the crop while the synthesis of organic elements in grain remained quite active, which resulted in increased levels of protein in F1 varieties and hybrids (Mero et al. 2023). As such, a combination of factors, short vegetative period, and dry weather conditions ensure increased levels of protein in grain, which is a primary goal in the selection of fodder barley grain in Kazakhstan.

To ensure the selection of high-protein parental forms of barley, statistical methods were used (dispersive and correlative analysis), which allowed us to establish the influence of various factors on protein amount per grain and to analyze the correctness of acquired data. Two-factor dispersive analysis has shown that external environment conditions during the vegetative period positively influenced the amount of protein in grain (91.8%), rather than geno-type characteristics of parental forms (5.2%). Interaction of genotype was shown to be a valid factor, yet mostly irrelevant (3.2%). Productivity correlation of crops with the amount of protein per grain on dryland farming was slightly negative (r = ‒0.2), and completely absent on iridous lands. During the transmission of agriculturally valuable characteristics, including the content of protein per grain, various types of inheritance occur (dominance, overdominance, and depression). Their percentage of correlation changes depending on parental form genotype and agroclimatic conditions of treatment. In arid condi-tions, on contents of protein per grain, intermodal type of inheritance and depression prevails (63%). One of the most important goals of this research is to select a parental form of barley from various ecological-geographical origination of source material. To select high-quality fodder grain donors, a crossbreeding method with top-cross was con-ducted. Saule (KazNIIZiR) and Harmal (ICARDA) samples were picked as father forms, while Arna, Kaiser, Syr Aryi (KazNIIZiR), Lignee (ICARDA), and St Sample (Ukraine) were picked as mother forms.

To evaluate the genetic characteristics of varieties, a method of determining combinative ability with top cross-breeding was employed. Overall combinative ability (OCA) and specific combinative ability (SCA) were evaluated. OCA refers to the collective performance and potential of an individual or a group of individuals in terms of their ability to contribute positively to desired traits when used in breeding or hybridization programs. It represents the capacity of parental lines or genotypes to combine their genetic attributes in a way that enhances the expression of desirable traits in their offspring. In turn, SCA refers to the unique and specific genetic interactions between two or more parental lines in a breeding or hybridization program. It measures the extent to which the combination of specific parents contributes to the expression of desired traits in the offspring.

The top cross method of combinative ability evaluation is deemed the most economical and widely used in selec-tion practice, which allows detection of donor characteris-tics of genotype, which are determined by the specific genetical structure of the variety. Such a procedure allows concentrating on material search, which holds not only valuable characteristics but also high combinative capability. This technique allows to significantly decrease the length of the selection process with the use of parental forms with an unknown or unavailable family tree. The selection of donors for crossbreeding on basis of combinative ability is fundamental for combinatorial analysis in simple and double interlineal hybrids. Results of the dispersive analysis on the research of combinative ability of barley parental forms on protein percentage attribute are shown in Table 2.

Table 2 . Results of dispersive analysis on research of combinative ability of barley parental forms on protein percentage attribute.

Variability origination	df	Ss	Ms	Ff	F0,05
OCAi × parents (♀)	5	78.4	15.68	130.7	2.4
OCAj × parents (♂)	2	156.2	78.1	779.4	3.18
SCA	10	89.5	8.95	81.4	2.01
Random deviation	34	3.6	0.12	-	-

i: lines, j: testers.

As a result of the combinative ability of lines and testers research on their F1 hybrids it can be concluded, that analyzed attributes have various systems of genetic con-trol. The percentage of protein was controlled with the use of adaptive, dominant, and epistatic interactions. Alongside the additive effect of alleles genes, the overall combinative ability of donors held non-allelic epistatic genetic interac-tions. Elemental relations of OCA (82.2%) and SCA (17.8%) variants indicated the prevalence of additive gene effects. The influence of the environment on the com-binative ability of lines and testers was also noted. Additive gene effects of parental forms had the most influence (Table 3).

Table 3 . Analysis of combinative ability on protein per grain contents in F₁ hybrid of fodder grain barley in Kyzylorda region environment.

Variability origination	Value	Veracity
OCAi	10.3	Р < 0.01
OCAj	105.6	Р < 0.01
OCA	24.8	Р < 0.05
OCA, %	82.2	-
OCA, %	17.8	-

Results of the research indicate, that in arid conditions and on saline soil of the Kyzylorda region, the variants Harmal, Lignee-527 (Syria), Arna, Seule, and Asem (Kazakhstan) have shown high definite OCA parameters on contents of protein. These samples were characterized with high OCA effects on the mass of 1000 grains, while Arna genotype – on the mass of grain with a spike. It is important to note, F1 hybrids, received on their basis, had high productivity as well. The most suitable donor for protein per grain in barley increase was the Arna sample as it has a favorable combination of OCA and SCA while additive values have exceeded non-additive. F1 hybrids: Syr Aryi × Saule, Lignee × Saule and St Sample × Harmal were the most effective in specific combinations (Table 4).

Table 4 . Analysis of overall combinative ability on contents of protein per grain in fodder barley in top cross.

Variety	Origin	Perc of protein, %	OCA ĝi, ĝj	OCA rank
Arna	Kazakhstan	12.6	+3.2	2
Asem	Kazakhstan	11.7	+2.8	4
Kaiser	Kazakhstan	12.8	‒2.5	9
Saule	Kazakhstan	12.1	+2.9	3
Symbat	Kazakhstan	13.0	+0.2	7
Syr Aryi	Kazakhstan	14.1	+1.2	6
Harmal	Syria	15.0	+4.0	1
Lignee-527	Syria	13.8	+2.6	5
St Sample	Ukraine	13.6	‒1.8	8

The following has been established during research: Saule variety has a positive and relatively high OCA value (+2.9) while the percentage of protein was significantly lower (12.1%) than in Syr Aryi variety (14.1%), Symbat (13%) and Lignee-527 (13.8%), which have lower OCA: + 1.2, +0.2 and +2.6 respectively. This indicates that high phenotype attributes of parental forms do not always show up in their descendants. As such, it is required to evaluate the combinative ability of varieties to determine donor capabilities of specific genotypes, native to their lines and testers. Specifier attributes for the selection of fodder barley are the contents of protein. Determining donors for high-quality grain varieties and hybrids is a lengthy and laborious process. It is required to find other appendant combinative ability characteristics of parental forms to ease the process in the field of research. Authors used determination coefficients and analyzed the OCA and SCA influence on morphological and productive characteristics with this intention (Fig. 4).

Figure 4. Functional link of protein per grain contents in fodder barley and other characteristics of combi-native ability.

Correlational analysis of agriculturally valuable charac-teristics of fodder barley variants of various ecological- geographical origination has shown, that on saline soils in arid environments of Kazakhstan, additive mutability of protein per grain content is connected to OCA parental forms on length of the vegetative period as well as a medium negative correlation with OCA and SCA of 1000 grain mass. Other characteristics have shown no real influence. As such, correlational analysis has shown, that on a selection of donors for new varieties and hybrids creation of fodder barley, the usage of combinative ability of parental forms on a mass of 1000 grain is possible as well as of OCA on length of the vegetative period.

Also, it should be emphasized that the use of molecular markers in the breeding process has many advantages, including improved breeding accuracy, accelerated breed-ing progress, ability to select for complex traits, and increased efficiency in achieving breeding objectives. By integrating molecular markers into breeding programs, breeders can make more informed and targeted decisions, leading to improved crop varieties with improved agrono-mic performance, disease resistance, quality traits, and other desirable traits.

Researched selection material for a parental form of fodder barley determining has counted 150 varieties of various ecological-geographical origination, most of them were from Kazakhstan (52%) and Syria (17%), which is caused by specific agro-climatic conditions of the Kyzylorda region (arid weather, saline soil). Research on the detection of protein-rich donors of barley in arid weather has been concluded earlier by other scientists (Almerekova et al. 2019; Fatullayev 2019; Akhmedova et al. 2021). Published data suggests, that to acquire varieties and hybrids with high protein levels per grain, genotypes and ecological-geographical origination of samples have substantial influence. As such, according to the results of Azerbaijani researcher P.U. Fatullayev (2019), perspective parental forms of protein-rich barley, cultivated on drylands, were such variants: S-331 (Mexico), Kharkovskyy-82 (Ukraine), Sa-37906, and Sa-34233 (Denmark) and Maxim (Russia), and S-331 (Mexico), Sa-34223 and Sa-52608 (Denmark), Copelia (France) for iridous soil. The works of Kazakh researchers (Almerekova et al. 2019) demonstrated, that protein-rich samples of American originations have better results in agriculturally valuable attributes in com-parison to local kinds from Kazakhstan, especially in rice crop rotation. This data set grounds for further search of a source of selective material for varieties and hybrids of fodder barley breeding not only in Kazakhstan and Syria collections but in other countries with less dry climates.

Protein percentage results of collective varieties of various ecological-geographical origination in Kyzylorda region environment research have shown, that level of protein per grain in barley was 11% to 15%. These values were lower than in the works of other countries’ authors: 15-17% on average with a mutability level of 13.5% to 20.3% (Baydyusen et al. 2021), which may be caused by weather conditions during the research. The study has indicated that majority of protein-rich barley varieties yield less grain, which is confirmed by other researchers’ works (Niu et al. 2022; Fatullayev 2019). Even more, the dependence of protein per grain content and mass of 1000 seeds was detected, which other researchers have also indicated (Fatullayev 2019; Akhmedova et al. 2021; Hagenblad et al. 2022). Nevertheless, amongst researched varieties of barley of various ecological-geographical origination, specific samples have been highlighted, which have a high percentage of protein (14.1-15.0%) and higher yield (322.3-442.2 g/m²). According to these attributes, the following samples were highlighted: Syr Aryi, 3/95-14, 99/99-2, and 99/99-8 from KazNIIZiR collection, as well as Harmal kind from ICARDA collection, which indicates a possibility of combining high yield and increased levels of protein per grain.

Evaluation of parental forms protein per grain per-centage has shown, that varieties with a short vegetative period can accumulate more protein, which is confirmed by results of other research (Akhmedova et al. 2021). As such, Ukrainian researchers recommend using kinds of early and intermediate crop groups as selective material for protein- rich kind breeding in the context of climate change and the worsening of moisture in the majority of territories. Dis-persive analysis has indicated a major influence of environ-mental conditions on amounts of protein per grain in periods of vegetation (91.8%), which was confirmed in research on the external environmental factor that influ-ences barley productiveness (Ceccarelli et al. 2008; Cai et al. 2013; Almerekova et al. 2019). According to data from American colleagues, many characteristics, which influence the quality of the grain, including protein percentage, heavily depend on factors of the environment. For example, a quality beer brewing kind may become unusable for primary use in drought due to the influence of aridness on the percentage of protein as well as on grain size. More-over, technical characteristics may change depending on the country of growth (Ceccarelli et al. 2008; Aipova et al. 2020). It has been established, that various forms of inheritance occur during the transition of agriculturally valuable characteristics of barley seeds, such as over-dominance and depressions, a percentage of which depend on parental form genotype and conditions of crop growth (technology, weather conditions, ancestors). In dry condi-tions on saline soils of the Kyzylorda region, an inter-mediary type of inheritance was best in the protein per grain levels. Information, that confirms this notion, has been published in the works of N.A. Pavlova et al. (2017), and G.B. Akhmedova et al. (2021).

The rich experience of selectionists indicates a majority of cases when crossbreeding of one line with another produced high-yield offspring, while the second line shows itself only in specific combinations (Karbivska et al. 2020). A reason for this is the dependence of hybrid vigor on line and varieties ability to interact complementarily with each other. As such, a complex system of inheritance factors interactions, which can only be instated through the shared and specific combinational ability of parental forms, plays a major role (Ignatova et al. 2015). Research of parental forms of combinational ability on their F1 hybrids has shown, that control of protein per grain in barley contents was done by additive, dominant and epistatic genetic effects, while the additive influence of genes has prevailed, which was shown by the high overall combinative ability of donors (82.2%). Additive mutability of protein per grain contents had a relatively strong connection with the parent’s overall combinative ability during vegetative period length, as well as average negative connection with overall and specific combinative ability on 1000 seed mass. Other agricultural characteristics of major correlation with combinative ability had no donors. The dominant influence of additive gene interaction of father forms in extreme agricultural conditions of the region of research has been highlighted. According to data of G.B. Akhmedova et al. (2021), in the rice systems near Aral Sea, additive gene effects of father forms were primarily influenced on protein contents of barley, while in the foothill territories of Almaty region father and mother forms had an influence.

It was stated, that Harmal, Lignee-527 (Syria), Arna, Saule, and Asem (Kazakhstan) variants have shown high levels of overall combinative ability on protein per grain content, while Arna variant was deemed the best donor in this vector. Acquired F1 hybrids: Syr Aryi × Saule, Lignee-527 × Saule, and St Vzyrets × Harmal were the most successful in specific combinations and kept their high hybrid vigor effect. Similar results in dry regions of Kazakhstan were also acquired by a variety of local researchers. According to their data, high effects of overall combinative ability were seen in Arna, Lagnee sample, and tester-kind Harmal. Such F1 hybrids were more successful in specific combinations: Syr Aryi × Marny; Odessky 100 × Harmal; Arna × Preria; Lignee × Saule (Akhmedova et al. 2021). This data confirms that the researched varieties of Kazakhstan and Syria origin (Harmal, Lignee-527, Arna, Saule, Syr Aryi, and Asem) are perspective and reliable material for the selection of varieties and hybrids of barley with a high percentage of protein per grain, and they can be used for Kazakhstan selection programs.

During the years 2019-2022, 150 samples of various ecological-geographical origination were analyzed to select parent forms to create varieties and hybrids of fodder barley in conditions of the Kyzylorda region. Most pro-spective donors were varieties of Kazakhstan collections (Asem, Saule, Arna, Symbat) and Syria (Harmal, Lignee- 257, Rihane-03). It has been concluded that kids of barley with a short vegetative period (Syr Aryi sample, of Kazakhstan origin) have the highest concentration of protein in comparison with intermediate and late crops (Obskoy sample from Russia). Dispersion analysis has shown that contents of protein per grain were influenced by environmental factors by 91.8%, while genotype pecu-liarities – by 5.2%. The influence of the genotype cha-racteristics was valid, yet irrelevant (3.2%). It is apparent, that in conditions of the Kyzylorda region, the intermodal type of inheritance and depression prevailed in the protein per grain levels (63%). In arid conditions and on saline grounds, the main factor in determining the analyzed attributes were non-allele interactions of genes, such as dominance, overdominance, and epistasis. Percentage relations of OCA (82.2%) and SCA (17.8%) have shown the prevalence of additive gene effects.

It is apparent, that additive mutability of protein per-centage per grain was characterized mainly by a relatively strong connection with OCA donors on the length of the vegetative period and an average negative correlation with OCA and SCA on a mass of 1000 seeds. Other charac-teristics have shown no real influence. Statistical analysis has shown that scale of phenotypical characteristic expres-sion in parental forms does not always indicate their high donor abilities. High levels of combinative ability on protein content were found in Harmal, Lignee-527 (Syria), Arna, Saule, and Asem (Kazakhstan) samples. They were characterized by the high OCA effect on the mass of 1000 seeds, while Arna variation – was on the mass of grain from the spike. The most successful F1 hybrids in specific combinations were Syr Aryi × Saule, Lignee × Saule, and St Sample × Harmal. As such, Arna, Asem, Saule, (KazNIIZiR), Harmal, and Lignee-527 (ICARDA) samples are the most perspective donors for the selection of fodder barley selection and are recommended to be included in hybridization programs in Kazakhstan. It is important to note, that the next stage of the selection process is the expansion of the adaptive potential of new varieties and hybrids of barley, as well as improvement of grain quality.

The research was carried out within the framework of program-targeted financing of scientific research of the Ministry of Agriculture of the Republic of Kazakhstan under the scientific and technical program “Creation of highly productive varieties and hybrids of grain crops based on the achievements of biotechnology-genetics- physiology-biochemistry of plants for their sustainable production in various soil and climatic zones of Kazakhstan”, BR10765056.