Study on Cultivation Technology of Rosa rugosa Thunb.

Nurbolat AIDARHAN Yanrui CHEN Haibaier HUOJIAAIHEMAITI Abulimiti YILI Haiji Akber AISA

Abstract Rosa rugosa Thunb. is a traditional medicinal and food plant in Hotan region, which has important medicinal and economic value. In recent years, the planting area in Hotan region has been expanding. This paper described the cultivation techniques, planting models and field management, pest control, harvesting and processing of R. rugosa . Based on the analysis of the advantages and cultivation techniques of developing the rose industry in Hotan region, the paper discussed how to accelerate the development of rose cultivation and deep processing industry in Hotan region.

Key words Rosa rugosa Thunb.; Medicinal and edible plant; Cultivation; Biological characteristics

Received: January 13, 2020Accepted: March 3, 2020

Supported by Western Youth Scholar Program of Chinese Academy of Sciences (2018-XBQNXZ-A-002); Autonomous Region Scientific Special Commissioner Poverty Alleviation Action Project (2019C01OO8).

Nurbolat AIDARHAN (1971-), male, P. R. China, associate researcher, PhD, devoted to research about medicinal plant resources.

*Corresponding author. E-mail:haji@ms.xjb.ac.cn.

Rosa damascene Mill. belongs to Rosa L. of Rosaceae. It is native to Syria［1］ and is now the main rose species cultivated in Bulgaria, the "Rose Kingdom".

Flos Rosae rugosae refersto Rosa rugosa Thunb. in Rosa L. of Rosaceae［2］. It is a kind of deciduous shrub plant, as well as a naturally optimized variety of world-renowned R. damascene Mill. R. rugosa is called rose, also called wild rose, which is a kind of world famous flower. In addition to its ornamental value, its use as both medicine and food is more important. It is a special resource in Xinjiang.

The producing area of R. rugosa is mainly Hotan region. R. rugosa  is called Kezelgul in the Uyghur language. It is distributed in the Hotan region of Xinjiang and the Kunlun Mountains.

R. rugosa has a history of more than two thousand years. The Hotan region is located in the hinterland of Eurasia, with sufficient light, abundant heat, and long frost-free period, having an average altitude of 3 000 m, which is very suitable for the growth of roses, and it is also the only highland rose producing area in the world［3］. R. rugosa has high economic value. It has practical value in the fields of medicine, food, cosmetics, washing products, tea, etc. , and is also an important flower shrub for urban and rural mountainous greening, soil and water conservation, and ecological restoration. It can be used to extract essences and essential oils. It has the functions of relaxing muscles, promoting blood circulation, invigorating qi, and relieving depression, and can be used as a substitute for saffron to treat gynecological diseases. Its root bark can be used as a dye for silk.

Rose is mainly distributed in Yutian, Moyu, Luopu, Pishan, Qira, Minfeng and other places of Hotan City.

Biological Characteristics of R. rugosa

R. rugosa belongs to Rosa L. of Rosaceae. R. rugosa blooms in the second year after cultivation. The above-ground part of the rose is generally 80-190 cm (stem height), having dense bristles and thorns on the stem, and 5-9 leaflets, which are oval or elliptic obovate, 2-5 in length, 1.0-2.5 cm in width, and have shiny and wrinkled surface and slightly pubescent leaf back. The petioles are solitary or aggregated. The fruit is spherical and brick-red.

Study on Cultivation Techniques of R. rugosa

Selection of cultivating land

R. rugosa is a kind of cold-tolerant, drought-tolerant, waterlogging-resistant sun plant. It has low requirements on climate and soil, and has strong adaptability. Therefore, we should choose loose loam or sandy loam with sufficient sunlight, good ventilation, high and flat terrain, loose soil and good drainage.

Field preparation

The land is prepared according to the requirements of traditional large-scale agriculture.The soil is applied with 37 500-45 000 kg of organic fertilizer per hectare, ploughed under to great depth (about 25 cm), and then leveled for cultivation.

Variety selection

The planted variety is R. rugosa , also called wild rose, which is a naturally optimized variety of R. damascene Mill. It has a history of more than two thousand years in Hotan region.

Propagation of R. rugosa

The main propagation method of R. rugosa is division propagation in large-area cultivation. There are also methods such as cuttage, grafting and burying roots. R. rugosa is generally re-ヽultivated for a maximum of 15-20 years. For division propagation, new branches with roots of more than 3 years old are generally preferred. The branch length is generally more than 30 cm, and the main root is at least 10 cm in length and has side roots and hair roots. And the plants should be free of injury and diseases. As to cutting propagation, after the leaves have fallen completely after the end of October, before burying into the soil, mature branches with a diameter of 1 cm or more were selected and cut with a length of 15 cm. The cuttings are bundled according to 20, and buried into the wet soil with the bud eyes downward. After half a month of dormancy, the cuttings are taken out for cultivating plantlets in a sunlight greenhouse. If there is no sunlight greenhouse, the cuttings should be stored in a cellar for preservation, and covered with sandy soil to ensure humidity and temperature and prevent the branches from freezing and deteriorating, and seedling raising or cultivation can be started at the end of March next year.

Cultivation techniques

Because there is a large population with relatively little land in Hotan region, most people choose crops such as wheat or garlic, Brassica campestris and other vegetables to interplant roses. Generally, the planting is performed in the direction from the north to the south, with a row spacing of 200-420 cm and a plant spacing of 50-100 cm, and the furrow width and planting depth are 30-60 and 20-25 cm, respectively. The theoretical number of plants per hectare varies according to the planting pattern, and generally ranges from 3 750 to 9 900 plants per hectare. The planting time is generally in mid-to-late October in autumn, after thawing in spring, and from mid-to-late March to mid April before germination. Generally, the survival rate in autumn is relatively high in the places where water is scarce, and the survival rate in spring is high in places with water.

Field Management of R. rugosa

Germination period of R. rugosa

Germination begins when the temperature is stabilized above 10 ℃. Rose in Hotan region generally begins to germinate in mid-late March.

Topdressing

The first time of topdressing is carried out before plant sprouting (bud stage) in early and mid March, in order to increase the amount of buds. Specifically, a furrow is dug at 20-30 cm away from the roots, into which 18 000 kg/hm2 of diluted farmland fertilizer and 225 kg/hm2 of diammonium and 150 kg/hm2 of potassium sulfate are applied. The second time is conducted in autumn. Specifically, a furrow is dug at 20 away from the roots, into which 22 500-30 000 kg/hm2 of diluted farmland fertilizer is applied, followed by ridging.

Irrigation

Irrigation is performed for the first time in Hotan region at about March 25, the second time at flower bud period before flowering which is about April 15, the third time at about May 10, and the fourth time in the period of May 25 to 30. Afterwards, irrigation can be performed for 1-2 times according to the actual situation after the flowering period. One time of winter irrigation must be carried out before burying the branches into soil in autumn. Attention should be paid to irrigation during the dry season. Drought will affect flower yield and quality.

Pruning

After flowering, senescent branches, wounded or pest-damaged branches are cut off generally from the end of June to early July in Hotan region, and pruning is performed once again in winter after leaves have fallen, which can promote the emergence of new branches of the plants and help ventilation, thereby increasing the number of flower buds in the coming year and increasing yield. Rose plants that have been growing for more than 5 years should be subjected to regenerative pruning before burying in the winter, which is mainly to truncate and cut off dense branches; and healthy growing branches of each plant are retained according to the growth situation, and the remaining roots are dug up and replanted.Root digging and replanting can also be carried out in spring.

Burying branches into soil

When the temperature is stabilized around zero, burying is carried out before freeze-up to help the roses to survive winter safely. When burying the branches, they are obliquely pressed into furrows dug first, and buried with soil of generally about 10 cm thick. The burying time is based on the winter weather in the local area, and is generally mid to late November in the southern Xinjiang area. After burying branches, winter irrigation should be performed when preventing running water from flooding the fields.

Flower Season and Harvesting of R. rugosa

Flower season of R. rugosa

R. rugosa begins to bud in middle and late April in Hotan region, and begins to bloom around April 25. The flower season ends in early June, and the flowering period is generally 35-45 d. According to local watering, the flowers can be divided into first-watering flowers (April 15 to May 15) with thick flesh, strong flavor, good quality and slightly lower oil content, second-watering flowers (May 10 to May 20) and third-watering flowers (after May 20). Therefore, roses should be harvested in stages and classified. As to harvesting standards, one is to harvest flower buds that have been fully expanded but not yet opened, which are collected before the full bloom period, followed by directly drying and packaging for sale, and the other is to harvest the petals after full blooming, for making sauce. The flowers from which the rose essential oil is extracted are harvested during the full bloom period, with the buds just opening, showing a cup shape, and the flowers with yellow hearts are better. When the heart shrinks and turns red, the quality decreases.

Picking time and yield

The picking time of R. rugosa is from 6:00 to 8:00 local time (not later than 12:00 o餭lock). At this time, the oil content is highest and the aroma is strongest. On cloudy days or when the flowers are not open, the picking time can be postponed according to the actual weather conditions. After three years, the output of R. rugosa is about 2 250-4 200 kg/hm2, and 4 kg of first-watering flowers get 1 kg of dried flowers. The ratio at other harvest time is 5∶1.

Disease and Pest Control of R. rugosa

Diseases and their control

The diseases are mainly black spot, rust, powdery mildew, and Capnodium mangiferae P. Henn.

Control methods: Diseased branches and leaves should be removed in autumn and winter, and burned intensively. It is necessary to strengthen cultivation management, control branch density, and enhance ventilation and light transmission. 75% chlorothalonil, 50% carbendazim, and 70% methyltobutin can be sprayed according to the instructions in the early stage of diseases.

Pests and their control

The pests are mainly aphids, Megachile rotundata , red spiders, and cutworms.

Control methods: Dead leaves are collected in autumn and winter and burn intensively. Winter larvae can be eliminated in combination with deep cultivation in winter. Adult pests can be caught with nets at the peak to reduce the source of pests. Leaves with eggs thereon are removed during the spawning period, or 10% imidacloprid, 90% trichlorfon or 50% phoxim can be sprayed according to instructions.

Existing Problems

Low yield and poor quality, cultivation techniques to be improved

At present, the average yield of roses in Hotan region is about 2 250 kg/hm2, and only 1 500 kg/hm2 in some places. The main reason is that the cultivation techniques are not standardized, and the field management cannot keep up (mainly the pruning technique and time are not appropriate, followed by field management), which causes problems in the yield and quality of roses.

Control picking time, pay attention to drying environment, and improve deep processing techniques

China餾 rose industry is still in its infancy and growth stage, and lacks high-end products, so the production of high-end rose products is a good starting point. To achieve high-end products, we must first attach importance to material quality; and second, the processing level, raw material utilization rate and product addition of roses in Xinjiang are currently low, and the industry is still in the rough processing stage.Therefore, if our inland enterprises improve the deep processing techniques, compared with other mainland rose producing areas, there is still much room for improvement.

Improve popularity of the products, and value product packaging

At present, the relatively well-known rose producing areas in China are Shandong and Yunnan, not Hotan. Hotan only has a long history of rose planting. It has a certain planting area and is not well known in the country. Many statistics and standards of medicinal materials about the rose industry do not involve R. rugosa . The main reason is that the research on R. rugosa and the development of rose products have been insufficient for a long time, and the publicity and promotion efforts can be imagined. On the other hand, many R. rugosa processing enterprises in Xinjiang do not pay attention to product packaging. The simplicity of packaging has affected the promotion and sales of products and reduced the added value of products. At present, the national level of awareness of rose products has increased year by year, and the demand for roses has also skyrocketed. Only rose essential oil has an annual demand of 5 000 kg, while its domestic production is only about 1 000 kg［4］. The most important components of rose essential oil are citronellol and geraniol, while the content of citronellol in Chinese rose essential oil is 8.3 times that of Bulgarian roses and 5.6 times that of French roses, and the content of geraniol is 249.8 times that of Bulgarian roses and 124.9 times that of French roses［5］. It is estimated that the current average annual demand growth of rose products in China is as high as 12%-14%, and the capacity growth is about 8%. The market demand gap is more than 60%. The next 5 to 10 years will be the rapid development of edible roses［6］.

The Hotan region has the advantages and conditions for developing the rose industry. If we seize the development opportunities of the rose industry, strengthen enterprise technological innovation, develop new rose products and improve the deep processing techniques of rose, the development prospects of the rose industry will surely become more and more bright. To attract farmers to actively invest in rose cultivation and increase income plays an important role in poverty alleviation in Xinjiang, especially in the Hotan region, and produces good economic and social benefits.

Agricultural Biotechnology2020

References

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［3］ SUN YM.Analysis of the development status of Rosa rugosa Thunb. planting industry［J］. Xinjiang Agricultural Science and Technology, 2014(3): 36-37. (in Chinese)

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Editor: Yingzhi GUANGProofreader: Xinxiu ZHU