The article presents the results of research on the growth, development and respect for the basic factors of the environment, the appearance of decorative merit varietal diversity of Zizyphus jujuba Mill in a light brown soils condition. Identified promising varieties for landscaping, gardening and private farms.
Rarely found in Russia woody plants complex jujube (jujube, Chilon, jujube) – Zizyphus jujuba Mill of the family Rhamnaceae Juss. include about 50 species and 400 species and varieties. They grow mainly in tropical and subtropical zones. In Russia wild one species (Zizyphus jujuba) and two (Z. lotus, Z. mauritiana) introduced. In gardening cultivated mainly because of the beautiful bright green glossy foliage and distinctive appearance. Some species of this genus (Zizyphus jujuba, Z. lotus, Z. mauritiana) is used as a fruit.
Figure 1. General view of the objects of study (FSUE «Volgograd»)
Figure 2. Zizyphus jujubа in phenophases “greening”
Zizyphus jujuba grows in the Transcaucasia and Central Asia mountain, central and northern China; Korea; India; West Asia; Mediterranean. Area of industrial plantations in China reached 200 thousand hectares In natural phytocenoses jujube is widely found in India, Afghanistan and Iran, Tajikistan and Turkmenistan to the south; grows in dry sunny, stony and rocky slopes of river valleys, hills and mountains. [1]
It is currently used as an ornamental tree species in India, China, Japan, Africa, Australia and America. Since the end of the twentieth century, Zizyphus jujuba is becoming increasingly popular in the south of Russia. It has been successfully introduced into the culture in the Krasnodar and Stavropol Territory. In the twenty-first century begins a trend move the plants in more northern areas.
Frost-resistant varieties of Zizyphus jujuba are scientific and practical interest for the southern regions of the Lower Volga region. In the Volgograd region (Federal State Unitary Enterprise “Volgograd” VNIALMI RAAS) conducted large-test (Ta-yang-Zao, Southerner) average fruited (dates, friendship), small-fruited (Sochi, Temryuksky) jujube varieties derived from the All-Russian Research Institute of Floriculture and Subtropical Crops (figure 1).
In a culture of the time required for all sorts of phenological phases are close together, especially in the initial period of the growing season, due to the rapid growth of positive temperatures in spring and summer (figure 2).
In large-fruited varieties (Ta Yang Zhao) jujube there is a danger of damage autumn frosts due to a longer growing season.
In the selection of varieties should pay attention to the possible impact of the whole complex of adverse factors. Under the conditions of the Kuban and Stavropol foothills installed endurance of this crop to frost up to – 30 ° C [1]. There is evidence of low hardiness in the Lower Volga annual accessions unabi that frozen to the level of snow cover in the severe winter of 1998/99. In the spring of next year, and the industry has successfully developed normally. [2]
Response to climatic factors was determined visually by the presence of damaged shoots.
If a young age trunks of damage above the snow cover was manifested in the form of cracks then as adults these lesions were not seen us.
Freezing of apical buds during deployment or unfolding of leaves, leaf damage ensued spring frosts were observed. Start regrowth of plants recorded in May, and at the end of the season the plants recovered their habit, indicating that a good regenerative capacity of dormant buds in all samples [3].
However, after the stressful conditions of the winter period there was a reduction of seasonal growth of side shoots from the previous year.
According to its habit jujube tree or spreadingly branched spiny shrub with angular-winding, naked, red-brown branches. Cultural forms have expressed bole. The leaves are leathery, glabrous, dark-green, glossy from oblong-ovate to broadly lanceolate on short petioles or nearly sessile with small stipules at the base.
Study of features of flowering and fruiting showed that flowering is confined to the period from the average daily temperature 22-24oС. Flowering duration – 20 to 35 days. The flowers are small (0.3-0.4 cm), bisexual, greenish-white, fragrant, with a delicate aroma. Pollination of flowers goes well with a relative humidity of 35-45% (figure 3).
The initiation of flower buds bloom occurs in the year, during the growth period of annual shoots in length, usually in July. Plants Zizyphus jujuba has a decorative blossoms. In some plants the flowers are scattered around the bush, others are gathered in the center of the bush, the third bloom profusely separate branches.
Under the conditions of the desert in a good light and heat modes pawned a large number of generative buds that had impact on the future of fruit and seed production. The longer growing season and higher average daily temperature, the more likely a high yield.
а b c
Figure 3. Zizyphus jujuba bloom (grade: A – Temryuksky b – Ta-yang-Zao, c – Dates) 
а b c
d e f
Figure 4. Fruiting varieties of jujube
For fruiting jujube in the Volgograd region required the sum of active temperatures (above 10º C) during the period from flowering to fruit ripening – 2200º-2500º C. Ripening fruit depending on the variety lasts from early October to early November. There is risk of damage to the fruit autumn frosts.
Zizyphus jujuba are formed harvest as fruit-bearing shoots, placed on a multi-year old wood and gains this year. During the period of full mass fruiting of ornamental plants is extremely high due to the bright color of fruits (red to dark brown, shiny). The main part of the harvest of all varieties ripens 2-3 weeks earlier than the late-fruits of growth. Fruit in the biological productivity of aboveground mass reach significant values – from 30 to 40% .They are vary in size, color and taste. The fruits may be round, is apple, pear-shaped, ovate, plum, fingerlike, oblong-elliptic. The chemical composition of the fruit varies widely. Chemical analysis of fruit in 2011, 2012. showed that in fruits jujube contains pectin to 10% and the presence of large amounts of ascorbic acid (up to 740 mg of%) as an additional source of vitamin C. Fruits contain a lot of sugar, nutritious and tasty (Figure 4).
Studying biological capacity to adapt varieties unabi to arid conditions can be viewed in two ways: as an adaptation of individuals in ontogeny or adaptation of varieties in general.
Based on the study of adaptation to be able to offer a wide variety and limited use: large-fruited for private gardening and farming; average fruited for greening purposes; small-fruited plants degraded landscapes to the creation of green areas in the suburban areas. Recommended for coating dry southern slopes, creating hedges and group plantings. Zizyphus jujuba is valued not only as an ornamental and fruit, but also as a honey plant. Particular attention is paid to the chemical composition of the fruit jujube due to their content of a large number of pectin and ascorbic acid, which allows us to give a good assessment process as raw materials for the confectionery and pharmaceutical industries.
Thus, based on the study of varietal diversity Zizyphus jujuba FSUE “Volgograd” VNIALMI RAAS the substantiation of bioecological and decorative properties and economic suitability, grade offered as an ornamental and fruit for the southern regions of the Volgograd region.