Screening of new sources of Hordeum vulgare genes for adaptive breeding in Aral Sea basin, Kazakhstan, for diversification of agriculture

The specifics of the soil and climatic conditions of the Aral sea region, Kazakhstan, primarily associated with salinization, various types of droughts, uneven distribution of precipitation during the growing season, and late spring frosts, make it necessary to create crop varieties with resistance to biotic and abiotic environmental factors. In this regard, the expansion of the area under crops of nontraditional salt-tolerant grain crops in the Kyzylorda region is one of the main directions of increasing the sustainability of agriculture in the region. Studies have shown that among the grain crops cultivated in the region, spring barley (Hordeum vulgare L.) is a reliable crop that can make the most of the region's bioclimatic resources to form sustainable yields. The purpose of this study is to create a new promising source material of barley based on a comprehensive study of collection material of various ecological and geographical origin by applying various methods of classical breeding. Based on a comprehensive assessment of the collection material of barley, a working collection of 250 varieties with agronomic resistance to environmental stress factors of the Aral Sea region was created. The selected samples are recommended for use in practical breeding in order to increase the adaptive potential of modern barley varieties.


Introduction
Lack of attention to climate change today has major economic implications for the future (http://agroarchive.ru/adaptivnoe-rastenievodstvo/; Budyko 1991;IPCC 2014). Not a single economy in the world today is able to actively withstand global climate change and the increasing frequency of extreme weather events. Particularly, the agricultural sector is most vulnerable to climate risk (Cho 2019). Providing food is impossible without a reliable plant genetic resources, which are the main source of improving crops and solving food security issues in any country. However, the decrease in varietal diversity observed in recent years in Kazakhstan has not only reduced the resistance of agroecosystems to weather fluctuations, but also significantly increased their genetic vulnerability. The length of the ear; The number of spikelets in an ear; The number of grains per ear; Weight of grain per ear and plant; Weight of 1000 grains; Grain weight from 1 m² Phenological observations and biometric analysis were determined according to the VIR methodology (Methodological guidelines 1981). Statistical processing of harvest data, including the least significant difference (LSD05) was done according to Dospekhov (1973). The coefficient of correlation was done in MS Excel, where r < 0.3 is a weak correlation; r = 0.3-0.7 is a medium correlation and r > 0.7 -strong correlation. Soil samples were analysed according to the methods described in Mineev (2001).

Materials
The objects of research were samples of barley of various ecological and geographical origin, presented in Table 2. The general view of the experiments' parts are shown in the Figure 1.  (ICARDA)  50  30  20  Iran  25  20  5  Turkey  10  10  -USA  24  15  9  Japan  5  3  2  Kazakhstan  116  95  21  Total  250  193  57 a) General view of the collection nursery b) Labelling of the samples

Results and Discussions
Based on the results of phenological observations, the samples from the Table 2 were ranked by ripeness group and their botanical varieties were determined. Of the two-row forms, there are mainly samples belonging to the "nutans" and "medicum" types, and four samples of the "inerme" type. Of the multi-row forms, genotypes of the "pallidum" -72% and "ricotense" -28% types are mainly found (Table 3). Nine samples were characterized by an extended growing season of more than 90 days and were assigned to the group of late ripening: Harrington, N942, N157, S26-3 (Japan); 23385 (Bolivia); 2/7-01, 2/3-01 (Syria); Scarlett, Maltz (Germany). In the collection nursery, the grain yield, depending on the ecological-geographical origin and climatic conditions of the year, varied from 0.25 to 7.5 tha -1 .
Of particular interest were the highly productive forms of two-row barley of the nudum variety and the multi-row variety coeleste, which can serve as parental forms in the creation of hulless barleyvarieties ( Figure 2).
The growing season. It should be noted that various conditions of moisture supply and temperature regime during the years of research allowed an objective assessment of collection samples of spring barley (Table 4).The most unfavourable in terms of weather and climatic conditions booting" (HTC = 0.03) and "booting-heading" (HTC = 0.04). The exception was the "sowinggermination" period, when the sum effective temperatures were insufficient for grain germination, which led to late sprouting of seedlings and a decrease in field germination. Therefore, in 2019, the growing season shortened and averaged 74-76 days. The share of early maturing samples in the collection was over 75%.
Although, according to the HTC, the entire growing season of 2017 and 2018 characterized as arid, but such critical periods as "tillering-booting" and "booting-earing" were characterized by a sufficient supply of moisture (HTC were 1.55 and 1.17, respectively, Table 4). This had a positive effect on the formation of generative organs and determined the high yield of barley in these years.  93 substantial impact on range-wide eco-geographical adaptation and improving the yield (Alqudah and Schnurbusch 2017) In the studied years, no differences found between the "sowing-earing" period, while statistically significant differences were observed in the "earing-ripening" and "sowing-ripening" phases. A significant correlation was found between the phase of "earing-ripening" and the duration of the growing season in multi-row (r = 0.49 -0.55) and two-row barley varieties (r = 0.57 -0.62).
Thus, under the conditions of the Aral Sea region, the phase of "earing-ripening" has a significant effect on the duration of the growing season, which must be taken into account when differentiating varieties by ripeness groups.
Based on the results of the analysis of phenological observations, a group of samples was identified that retains a short growing season regardless of climatic conditions. These samples are of interest as sources of early maturation in practical breeding. A distinctive feature of this group of samples is the elongation of the "tillering-booting" period, which is reflected in the high adaptability to the conditions of the Aral Sea region (Table 5). The study of spring barley cultivars under the conditions of rice-based cropping systems showed that field germination is largely determined by the sum of active temperatures during the "sowinggermination" period, which is confirmed by a high correlation coefficient (r = 0.71). This is due to the fact that in the rice-based crop rotation, barley is placed after rice, and the natural moisture of the soil is quite sufficient to obtain seedlings.In the given conditions, the limiting factor during the "sowinggermination" period was the lack of heat. So, on average in the experiment in 2017 at the sum of active temperatures = 133.7, field germination was 78%, in 2018 at the sum of active temperatures = 129.6 field germination was 77% and in 2019 at the sum of active temperatures = 115.7, field germination was 68%.There were no significant differences in this trait between two-row and multirow forms. The amplitude of variation in field germination in the context of genotypes increased from low to high levels (V = 9.5 to 93.2%).In general, the value of variability was 31.65%, which refers it to a highly variable trait, that is, this trait is highly dependent from the influence of meteorological conditions of the year. In general, among the studied lines and cultivars, up to 25% of the samples had low field germination (35-50%), and, depending on the environmental conditions, were characterized by high variability V = 35.4-62.3%.It should also be noted that along with the high field germination rate on saline soils, the intensity of the initial growth of barley is of particular importance. Genotypes with this trait in the initial phase of the growing season grow very quickly and intensively. This creates the best conditions for the growth and development of perennial grasses, shading them from direct sunlight, and most importantly, prevent the rise of salts to the soil surface.
In this regard, taking into account this adaptive trait, genotypes were identified in the collection nursery that combine high field germination and rapid growth in the initial phase of ontogenesis. They multi-row: B 024, K 614 (Japan); 5-72, 5-75, 5-88 (Syria); Pallidum (Ukraine) ( Table 6). As can be seen from Table 5, the average indicators of field germination in the selected samples were from 72 to 82%.For the stressful conditions of the Aral Sea region, these are rather high indicators. In our studies, a positive correlation was established between the number of productive stems preserved for harvesting and field germination (r = 0.721), which ultimately affects the formation of high productivity.
In this regard, an important feature that allows one to judge the adaptive properties of the studied genotypes at the early stages of ontogenesis is field germination. Therefore 6.9%, which is considered low varying, while in the multi-row group the coefficient was 17.6% attributing it to the medium-variability. Our results showed that under the conditions of the Aral Sea region, multi-row samples were highly susceptible to stress factors. Therefore, because of inhibition of growth processes, a sharp decrease in plant height observed in climatically unfavorable years (Table 7) the total grain productivity (Hay and Ellis 1998). In our studies, multi-row forms had a more developed leaf surface than two-row ones. Final grain productivity is the most important property of the variety, which is the goal of all agricultural production and therefore is the main factor for breeding. Over the years of research, 25 high  (Table 8).