STUDYING ZIZIPYHUS JUJUBA MILL. CV. IN SOUTHERN PART OF RUSSIAN HUMID SUBTROPICS

Cand.Biol.Sci. Kiseleva N.S., Cand.Agr.Sci. Кulyan R.V.

Federal State Budgetary Scientific Institution

“Russian Research Institute of Floriculture and Subtropical Crops”,

354002, Russia, Krasnodar region, c. Sochi, st. Yana Fabritsiusa, 2/28

e-mail:supk-kulyan@vniisubtrop.ru

Tel. 8-918-603-62-37

Introduction

The Black Sea coast under its natural-climatic factors is unique for cultivation of many rare subtropical fruit crops. Zizypyhus jujuba Mill. - rather new crop, perspective for cultivation in Krasnodar, Stavropol region, Crimea, Dagestan and in some other southern regions of Russia. Jujube is a subtropical fruit crop, rich in dietary and medical qualities, and special for its quite original taste. Besides, jujube is one of the most drought- and winter-resistant crops (this crop is capable to tolerate thirty degrees below zero).

In various regions of the world it is called variously: jujube, sometimes jujuba, chilon, red date, Chinese date, Korean date, or Indian date, etc.

Jujube fruits may differ both in shape and colour (from light yellow to red-brown). Besides, the taste of fruit pulp also depends on a concrete cultivar. Usually jujube fruits taste sweet-sour, and can be stored in dried form throughout a year, acquiring special delicate aroma. They contain ascorbic acid, proteins, sugars, acids, vitamins (A, B, C, beta-carotene), microelements, amino acids, lipids, organic acids (tartaric, malic, etc.), coumarins, sterols, flavonoids (myricetin, kaempferol), triterpenes and triterpene glycosides, saponins and alkaloids isoquinoline (azimiloban and stefarin) [1, 3, 6].

Thanks to its nutrient, medical and dietary properties jujube crop is widely educed in a number of countries, especially in China which is native and where extensive industrial plantings are cultivated. Nowadays jujube is cultivated in Japan, Korea, India, Afghanistan, Iran, Italy, France, Portugal, USA, Tajikistan, Turkmenia.

The first cultivar plants of jujube were delivered to Sochi from China in 1955. The primal object of studying new jujube cvs. has still been a selection of the most fruitful, winter-resistant, large- and average-fruit-sized cvs., resistant to pests and diseases, having high taste quality and rich in bioactive substances for further selection and introduction into production.

Objects and methods

The given research was conducted on an experimental plot of collection plantings, located in brown wood, weakly unsaturated soils (Khosta district, Sochi).

Research objects were 20 cultivar-forms.

The cultivars were studied by the methods developed in Nikitsky Botanical Garden [5]. We determined phenological phases in various jujube cvs., their productivity, damage rate from pests and diseases, and conducted pomological description of fruits.

Results and discussion

Long-term observations and analyses have allowed us to group cvs. and forms introduced in the collection by the following phenological phases: beginning and ending of vegetation, initial blossom, ripening, productivity, fruit sizes and other indicators.

In comparison with traditional fruit crops, jujube is special for its late vegetation. On the Black Sea coast of Krasnodar region jujube vegetation begins with bud swelling which was recorded in the first- second ten-day periods of April.

Data analysis of phenological observations has shown that there is no significant difference in terms of vegetation beginning in different cvs. On the average it makes up 5-7 days. The same is about budding and blooming terms. However, the terms of fruit ripening differ in cvs. and forms (up to 20-25 days).

It is revealed that buds in Tha-yan-tszao cv. swell earlier and blossom in late April - early May at daily air temperature about 13,5⁰С, thanks to what plants do not suffer from unfavorable vernal temperatures. Cvs. Druzhba, Sovetskiy, Ya-tszao, Kitaiskiy 2А and Burnim refer to early-ripening.

Later blossoming and quite early ripening (in mid October) is an important biological property of this crop protecting plants from late vernal and early autumn frosts.

In the conditions of Sochi jujube starts blossoming in the first part of June and concludes in August at daily air temperature 22-24⁰С. Pollination of flowers passes favorably at a relative air humidity (35-45 %). Long-term observations have shown that the longer vegetation period is and the higher daily average temperatures are, the higher and more stable yields may be expected [2].

As for blossoming terms, earlier beginning is noted in cv. Tha-yan-tszao – which is 5-7 days earlier than the great bulk of cvs. Duration of blossoming ranged in different years from 28 till 54 days, depending on biological singularities of genotypes.

Shorter blossoming term is noted at cvs. Khurmai and U-sin-khun - 9-12 days, the most durating - at cvs. Tha-yan-tszao, Vakhsh, Burnim - 27-32 days.

Jujube is a cross-pollinated entomophilic plant. From 100 to 250 thousand flowers blossom abundantly in one plant (in eight-year-old plant). The period from mass blossoming till fruit ripening makes up 65-90 days at daily air temperature about 22-24,6⁰С.

The terms of jujube ripening in Sochi are late September - early October, Tha-yan-tszao blossoms before others.

The observations have shown that all jujube shoots completely ripen before autumn frosts; 2 basic types of fruit-bearing shoots are characteristic for this crop: in an accretion of the current season's increment; in nodes of growing side shoots; in paleocrystic “lambourds”[2, 4]. Leaf shedding and transition of plants to rest happens after mass blossoming that finishes in October. For small-fruited forms the dormant period makes up 193-197 days; for large-fruited and medial -fruited cvs. (Burnim, Finik) it is two weeks shorter, and for such cvs. as Tha-yan-tszao, Vakhsh, U-sin-khun - 20 days.

Jujube is an early-ripening crop, which starts fruit-bearing on the second-third year after planting, medial productivity among cvs. is about 100-120 c/ha, for separate cvs. (Vakhsh, Burnim, Yuzhanin, Ya-tszao) it may reach 200 c/ha [4].

According to ripening terms, we have selected the following: early cvs. (middle September) - Burnim, Tha-yan-tszao, Kitaiskiy 2А, middle cvs. (October) - Vakhsh, Sio-bai-tszao, Ya-tszao, Hurmai, Druzhba, Da-bai-tszao, Sovetskiy, Yuzhanin, Finik, and small-fruited forms Kavkazskiy, Karabakhskiy and late cvs. (late October-early November) - U-sin-khun, Gissarsky, Dekorativnyy 98.

Jujube fruits are varied in form, mass, colour of pulp and peel, and taste. They have various sizes which largely depend on cv. signs. Kernels are usually cylindrical, pear-shaped and roundish; they differ in surface and acuteness.

By fruit size cvs. and forms are subdivided as follows: large-fruited cvs. (medial fruit mass is from 10 g and more) - Vakhsh, Tha-yan-tszao, U-sin-khun, Khurmai, Sovetskiy, Yuzhanin, Kitaiskiy 2А, Kavkazskiy A; average-fruited cvs. (medial fruit mass is from 5 to 10 g) - Burnim, Sio-bai-tszao, Druzhba, Da-bai-tszao, Dekorativnyy 98, Finik, Kitaiskiy 52; small-fruited cvs. (medial fruit mass is from 3 to 5 g) - Karabakhskiy, F-201, Gissarskiy, Ya-tszao, Kavkazskiy. Fruits having mass less than 3 g, are usually used for cultivation of root stocks.

Jujube cvs. like other fruit crops are divided to table (dessert) and canning.

Table cvs. are characterised by large and medial fruits with attractive appearance, leveled in size, with intensive colour, dense, but not hard peel, juicy pulp of pleasant harmonic sweet-sour or sweet taste, small kernel (the percent pulp should not be less than 95 %). Such cvs. include Ya-tszao, Yuzhanin, Vakhsh.

Canning cvs. are desirable to have the same qualities as above, but powdery consistency of pulp and small fruit are allowed. Canning cvs. include Gissarskiy, Sio-bai-tszao, Druzhba, Dekorativnyy 98.

The most appropriate to prepare dried fruit and candied peels are early-ripening cvs. Tha-yan-tszao, Sovetskiy, Kitaiskiy 2А.

The following cvs. and forms can be referred to general-purpose: U-sin-khun, Da-bai-tszao, Kitaiskiy 52, Yuzhanin, Vakhsh, Burnim, Khurmai.

We described the most promising cvs. for cultivation in the south of Krasnodar region.

Tha-yan-tszao cv. (Chinese origin). A vigorous, sprawling, thornless tree. The cv. is large-fruited, early-ripening (third ten-day period of September), fruit mass can reach 16-37 g, average yielding - 100 c/ha. Additional advantages are frequent lack of kernel, and early ripening: the first harvest can be taken in 2-3 years. Fruits are mainly used for canning.

Khurmai cv. is large-fruited, early-ripening (third-forth ten-day period of September) – average fruit mass can reach 18-40 g; high yielding. Ripe fruits can remain in trees within 2-3 weeks, thus they are cured slightly and their taste becomes better. Fruits are transportable, at +4⁰С can be stored for about 2 months.

Yuzhanin cv. (Tajikistan, A. Massover B. L). Large-fruited, early-ripening (first ten-day period of October), high yielding (120-140 c/ha). Fruits are mainly used for canning.

Vakhsh cv. Selected at Vahsh Experimental Station of Subtropical Crops, Tadjik Research Institute of Farming and Zoning in 1981. Large-fruited, average fruit mass is 14 g, but it can be larger, pulp is sweet. It becomes especially tasty after ripening (the complete coloration), having hung in a tree for a week or more.

Sovetskiy cv. Large-fruited, average ripening, originated from Tajikistan. average fruit mass is 11 g, maximum - 20 Taste is sweet, slightly sour, pulp is dense and juicy; high yielding. Fruits are used for preparing stewed fruit, jam, candied peels. Disadvantage – fruit cracking in a tree.

Kitaiskiy 2 A cv. The tree is about 2,5 m with a compact crone, thornless. Fruits are large, about 11-20 g, start ripening from the second half of September (15-21.09) till late October (23-30.10). High yielding. Fruits are suitable for fresh consumption, technological recycling and drying.

Conclusion

Among the studied cvs. and forms of jujube, according to fruit sizes, we have selected the following: Tha-yan-tszao, Kitaiskiy 2А, Sovetsskiy, Yuzhanin, Khurmai; according to yielding: Burnim, Sovetskiy, Yuzhanin, Ya-tszao, Da-bai-tszao; according to a complex of economic valuable signs (early terms of ripening, average and large fruits having good taste, high and regular productivity): Kitaiskiy 2А, Burnim, Sovetsskiy, Yuzhanin, Tha-yan-tszao. Further studying of the gene pool recorded in Russian Research Institute of Floriculture and Subtropical Crops will allow us to specify characteristics of the promising cvs. and forms and determine useful signs.

References:

1. Vorontsov, V.V, Shteiman U.G. Cultivation of subtropical crops// Kolos, 1982.-P. 225-227.

2. Ksenofontova, D. V. Prospects of jujube cultivation in conditions of Krasnodar region / D.V. Ksenofontova, L.V. Pervitsky, V.I. Yakimenko / Coll. Prs of Russian Research Institute of Floriculture and Subtropical Crops, Sochi, 1994, issue 38 - P. 215-227.

3. . Mikeladze, A.D. Subtropical fruit and industrial crops / A.D. Mikeladze // M .: Agropromizdat, 1988. - 290 p.

4. Ponomarenko, L.V. Biological features and economic evaluation of Chinese dates in Kuban horticultural area: Author. Dis. cand. Agr. Sci. / Larisa Ponomarenko - Krasnodar, 2006. – 26 p.

5. Sinko, L.T. Guidelines for primary jujube cultivar studying / L.T.Sinko // Yalta: Nikitskiy Botanical Garden, 1976 – 42 p.

6. Sapiyev, A.M. Subtropical crop growing in Russia / A.M. Sapiyev, V.V.Vorontsov, V.V.Koblyakov // M .: Agricultural Science, 1997. – 184 p.