Prospects for the introduction of fodder species Artemisia into culture

. In many desert communities, the basis of pasture ecosystems are species of the genus Artemisia, which are edifiers of plant communities in the vast territories of the Central Asia desert zone. Sagebrush pastures with a diverse set of plant species and life forms are used in desert animal husbandry all year round. Artemisia spp. is good fodder pastures plants. Green twigs contain 16.9% protein, 4.4% fat, 39% nitrogen-free extractives. Artemisia diffusa , А. turanica are common on desert gray-brown and gray-earth soils with different granulometric composition, Artemisia halophila has a narrow ecological area confined to saline soils. The fodder mass of Artemisia spp. serves as the main type of sheep fodder and is especially appreciated in the autumn, winter and early spring periods. As a result of irrational use, the natural sagebrush pastures of deserts are degraded and need to restore their fodder productivity. All three wild–growing species – Artemisia turanica , Artemisia diffusa , Artemisia halophyla in culture conditions accelerate the passage of phenological phases in the process of ontogenesis. Individuals of species populations of sagebrush develop faster in cultural conditions than in natural sagebrush communities. In the culture conditions the process of ontogenesis, skeletal axes of the shrub are laid at the base of the maternal shoots in young individuals, in the second or third year of life, the tested species of sagebrush form a morphologically full-fledged life form of a semishrub with a feed productivity 3-5 times higher than the yield of natural pastures. In the conditions of Artemisia spp. culture, they grow well and quickly. Many individuals enter the fruiting season in the first year of life.


Introduction
Artemisia diffusa Krasch.and Artemisia turanica Krasch.are semi-shrubs 30-40 cm high with strongly dissected grayish leaves [1].Artemisia diffusa and Artemisia turanica are widespread on desert gray-brown and gray soils of different mechanical composition.At the same time, A. halophyla Krasch.has a narrow ecological range, confined mainly to saline soils and does not extend these habitats [2]. A. halophyla is spread in the Aral-Caspian, Kyzylkum, and Karakum [2,3].Artemisia is resistant to abiotic stress [4].

Research methodology
The system of observations and records of Artemisia seeds germination, their growth, development, fruiting, seed and fodder productivity was carried out in accordance with the "Methodological guidelines..." [6].
The studies were conducted in two ecologically different areas of the Central Asian desert.
Piedmont desert of the Nishan "steppe".The experimental site is located at an altitude of 354 m above sea level.The soil cover is represented mainly by light gray soils.A characteristic feature of the soil profile is its layered structure: horizons of light, medium and heavy loams, as well as sandy loam alternate.The soils are largely saline and can be classified as saline.The content of water-soluble salts reaches up to 1.35-2.77%which are mainly Na2SO4, CaSO4 and NaCl.According to the total amount of water-soluble salts, the considered soils are characterized by sulfate and chloride-sulfate types of salinization.Humus content in the rooting layer is 0.02-1.86%.Groundwater occurs at a depth of 12-14-20 m.Mean annual air temperature is +14.8°C, with maximum of +47°C and minimum of -27°C.The coldest month is January, with temperature sometimes dropping to -30°C.Mean annual precipitation is 222 mm [7].
Wormwood-ephemeral Carnabchul desert.The experimental site is located at an altitude of 310 m above sea level.The dominant soil type is light gray soil and transitional from light gray soil to gray-brown.Soils are of stratified structure: horizons of light loams are replaced by medium loams, gruss or sandy loams, non-saline and slightly saline.Humus is contained in insignificant amounts.In the upper layers, its content varies from 0.30-0.79 to 0.81%, and in the lower layers, its content drops to 0.17%.Groundwater occurs at a depth of 14-20 m.Mean annual air temperature is +16°C.In June-July it reaches 40-45°C in the shade, and in January it sometimes drops to minus 20-30°C.Relative humidity for the year

Results and discussion
In the process of ontogenesis of Artemisia turanica, Artemisia diffusa and Artemisia halophila fodder species, important stages in their life cycle are the phases of flowering and fruit formation in the conditions of the Central Asian desert.In the studied species of Artemisia the inflorescence is a anthodium of cylindrical form, strongly pubescent.Flowers are usually arranged three to seven on one bare peduncle of the anthodium, with five stamens.Usually from one inflorescence consisting of five to seven flowers only one or two produce fruit, the rest are sterile.On average, there is one developed fruit per anthodium.
All Artemisia flowers are of both sexes and very small -about 2-2.5 mm long.In the anthodium, the outermost flowers bloom first, followed by the middle flowers, but without a definite sequence.
At the very beginning of flowering, the upper edges of the flower petals are closed.Then the petals diverge, and the tips of the stamens are seen from the top of the flower.It soon burst, and a mass of light-yellow pollen fills the top of the opened flower.During the day, the stamens extend further out of the flower and pollinate.On a still sunny day, the pollen in the flower can be seen for hours, but in strong winds it is blown away.If such a flower with pollen is carefully separated and unfolded under a magnifying glass, one can see inside it a short column and close 2 lobes of the stigma.They have their own pollen, but it does not germinate, as at this time the stigma is not mature.
In a flower in which the stamens have just begun to pollinate, the upper edge of the stigma lobes is at the level of the central part of the flower.No growing pollen stigmas or columns of the same age were found in the pollen tubes examined.
By the end of the first or second day of flowering there is an increased growth of the column, the lobes of the stigma are brought out above the corolla of the flower and widely extended.At this time, the stigmas are firm and shiny due to the secretion.The flower remains in this state for one more day.Since its pollen is all expelled by this time, it can only be pollinated by the pollen of another flower.Later, the stigma loses viability, which can be determined by its appearance (loss of turgor), shrivels up, but does not always fall off.Often, many days after pollination, the dried lobes of the stigmas of several flowers can be seen in the developing anthodium.
The anthodium blooms for 4-12 days depending on the number of flowers.Thus, the anthodium that bloomed on September 25 faded on October 4-5.Flowers in anthodium are set from about the middle of July, and their development lasts until the end of September.Flowering begins in late September to early October.
Experiments were conducted to find out the type of pollination of Artemisia.On September 25, anthodia that were supposed to bloom soon but had not yet bloomed were carefully isolated with bags.On November 10, all isolated anthodia were cut and carefully examined in the laboratory.We isolated 127 anthodia of Artemisia turanica, which contained 1013 flowers, but no seeds were set, and 58 anthodia of Artemisia diffusa, which contained 808 flowers, but no ripe seeds.
To determine seed set in Artemisia when pollinated with pollen from flowers of other anthodia of the same plant, 6 twigs on 6 plants were isolated.There were 13, 15, 16, 17, 31, and 45 anthodia on the twigs.There also were 105, 108, 158, 129, 214, and 321 flowers in them, respectively.No set seed was found in these anthodia in November.In the study of anthodia developed without isolation under conditions of free pollination, in Artemisia turanica and diffusa, 100 anthodia each in three repetitions of wilted seeds were examined.On average it was 35 and 26%, respectively.Thus, autogamy and geitonogamy are not characteristic of Artemisia turanica and diffusa.
In the ontogenetic development of forage species of Artemisia, the fruiting phase is the final stage in their life cycle.
Artemisia turanica, Artemisia diffusa and Artemisia halophila have an obovate seed, flattened on the sides.Fruit shells are light gray, with ribs clearly visible on the surface of the seed.Seed pod is 1.5-1.8 to 1.9-2.0mm long, and 0.6-0.8mm wide.
Seeds (fruits) of forage Artemisia species germinated under favorable conditions of thermal and moisture regimes.In this regard, we have carried out special studies to establish the optimal regimes for germination of Artemisia seeds.Experiments on the influence of temperature and humidity on the germination of Artemisia diffusa seeds showed that more vigorous germination was observed at variable temperatures (31-13-31 °C).Also, even germination of seeds occurred when they were frozen for four days and then germinated in chambers with a temperature of °C.Such experiments were conducted with seeds one year after they were collected.
Experiments conducted to study the germinability of freshly collected seeds of Artemisia diffusa and different years of their storage allowed us to conclude that the laboratory germinability of Artemisia seeds is about 30% with fluctuations in the range of 13-47%.Seeds have a post-harvest dormancy period from which they emerge (within 1-2 years) when stored in laboratory conditions or after 30-40 days when stratified.
Laboratory germination of halophila seeds showed that freshly harvested seeds had a germination of 46-63%.After 14-month storage it increased to 75.3%.Field germination was much lower and amounted to 10%.
Artemisia seeds sown in February sprouted in mid-April.The onset of phenophases was as follows: shoot formation in May, budding in mid-July, and flowering in September.All populations of Artemisia develop well in the first year with often fruiting.In subsequent years, the onset of phenophases during ontogenesis was accelerated and was as follows: regrowth was in April, intensive growth was in May, budding was in June, flowering was in August, autumn vegetation took place in September-October, and seed ripening was in November.The growing season is 230-237 days long.
Table 1 summarizes the dynamics of stand density and survival rates of Artemisia species under culture conditions in piedmont and wormwood-ephemeral desert.In the first year, survival of individuals of all species ranged from 42.2-51.9% of the maximum number of emerged seedlings in spring (Table 1).The survival rate of plants of all Artemisia species gradually increases with age and is as follows: by the end of the sixth year of vegetation in the piedmont desert, it amounted to 23.8% in Artemisia turanica and 40.2% in Artemisia diffusa.In wormwood-ephemeral desert by the end of the sixth year of vegetation, the survival rate of individuals in Artemisia halophila was 20.1%.Artemisia halophila, sown on gray-brown soils of light mechanical composition in South-Western Kyzylkum, gave good sprouts.In spring there were 188,120 plants on 1 ha.By the end of the first year, 22.6% of the plants had survived, and by the end of the fourth year -6.3%.Being a plant of saline habitats, when transferred to upland conditions, Artemisia halophila gradually dies both in the piedmont desert and in South-Western Kyzylkum.Only the ecological conditions of the Carnabchul desert turned out to be the most favorable for the growth of Artemisia halophila.
Emerging seedlings barely reach 1.5-2 cm in height in April-mid-May.It is 9.5-13.5 cm in late June, and 19.6-22.1 cm in August.At one year of age in the piedmont semidesert, the height of Artemisia individuals in the population reached 21.9-26.1 cm, while in wormwood-ephemeral it reached 36.7-41.0cm (Table 2).In the second year, the height of bushes of all examined species is slightly higher.In subsequent years, it is at about the same level in all examined Artemisia species.At the same time, new twigs are formed.When growth is complete, generative twigs dry out to more than half of their length.The species tested in the wormwood-ephemeral desert are well developed and characterized by greater stature.
In natural growing conditions on gypsum light medium and light loamy gray soils, the roots of Artemisia diffusa penetrate to a depth of 80-120 cm.Lateral roots are usually well developed and extend horizontally up to 1 m.The majority is concentrated at a depth of 30-40 cm.There are many ephemeral roots in the upper-most layers of soil.Under cultivation on light loamy soils, root system develops faster than the above-ground part.At the age of one year the roots penetrate to a depth of 95-120 cm, and at the age of 2.5 years in culture to a depth of 280 cm.The root system of adult plant does not have a well-defined main root due to severe reduction.

Table 1 .
Dynamics of stand density and survival rate of Artemisia species during cultivation in Note: in the numerator absolute figures in pcs/ha, in the denominator -%.

Table 2 .
Growth performance of some Artemisia species during cultivation in Central Asian desertsIn the Carnabchul Desert, we dug up root systems of Artemisia diffusa in the wild and in cultivated areas.Soils are light gray soils, light loamy and sandy loam by mechanical