Practical Cultivation Techniques of Gardenia jasminoides Ellis for Flowers-Fruits in Hunan Province

Yan YANG, Yuxi TANG, Pingshu QIN, Xinghua WU, Jie TANG, Lei LI, Yongjin LI

1. Hunan Academy of Forestry Sciences, Changsha 410004, China; 2. Nanhua National Forest Management Service, Fenghuang 416200, China; 3. Fenghuang County Forestry Bureau, Fenghuang 416200, China

Abstract In order to protect and develop the local resources of Gardenia jasminoides Ellis with Hunan characteristics, this paper uses the existing technology, analyzes the existing achievements in the cultivation of G. jasminoides Ellis, investigates and analyzes the actual situation of the seedling base and cooperatives in Hunan, and collects the relevant index data related to the cultivation of G. jasminoides Ellis. This paper summarizes the practical techniques related to land selection, soil preparation, seedling breeding, afforestation technology, tending management, pest control and so on, in order to provide reference basis for planting and cultivateon and industrial development of G. jasminoides Ellis in Hunan.

Key words Hunan Province, Gardenia jasminoides Ellis, Dual use of flowers and fruits, Cultivation

1 Introduction

GardeniajasminoidesEllis, an evergreen shrub of Gardenia in Rubiaceae, is included in the first batch of medicinal and edible plants issued by the Ministry of Health of China. Its green leaves and red fruits are commonly used for landscaping and courtyard ornamentation in China. Gardenia has a pleasant aroma and is a good source of honey. At the same time, it is not only an ideal raw material for extracting essential oils and pastries, but also a delicacy for rural farmers. Its root, leaf, flower, fruit and bark can be used as medicine, which is the raw material of dozens of proprietary Chinese medicines and a special medicine for the treatment of icteric hepatitis, contusion, hypertension, diabetes and so on. Gardenia yellow pigment and gardenia blue pigment extracted from its fruit are rare natural pigments, which are widely used in food, medicine, daily chemical and cosmetic industries. The effective ingredients such as saffron and geniposide in the fruit have the effects of reducing blood lipids and antioxidation, and are the best natural health care products favored by people at present. Thus it can be seen thatG.jasminoidesEllis is full of treasures, is a multi-purpose eco-economic tree species, and has broad prospects for development and utilization.

G.jasminoidesEllis has been used in China for thousands of years, its resources are widely distributed and it has strong adaptability. It has great potential in the fields of medicine, food, agriculture and make-up. It is a new industry that transforms "clear waters and green mountains" into "gold and silver mines" to shake off poverty and become rich. The planting area ofG.jasminoidesEllis in Hunan province has reached more than 3 000 ha, accounting for more than 60% of the total area of China. The Provincial Department of Agriculture and Rural Areas has listed it as one of the key industries of traditional Chinese medicine in the province, andG.jasminoidesEllis in central Hunan has been included in the national geographical indication product development plan. It can be seen that our province has promoted theG.jasminoidesEllis industry to a new important height. However, due to the backward cultivation mode ofG.jasminoidesEllis seedlings, the low cultivation and utilization rate of improved varieties and strong seedlings, the lack of cultivation management technology system for both flowers and fruits, and the lack of a specific and feasible and efficient cultivation standard to follow, the cultivation ofG.jasminoidesEllis in Hunan shows the present situation of "only quantity, no yield". In view of this, relying on the regional characteristics of Hunan and the needs of the industrial development ofG.jasminoidesEllis, the dual-purpose cultivation techniques for flowers and fruits ofG.jasminoidesEllis were studied and summarized, which can not only optimize the planting mode ofG.jasminoidesEllis, but also further strengthen the scientific guidance to the planting industry ofG.jasminoidesEllis through this practical technology, so as to drive the poor households to support themselves, shake off poverty and become rich, and help the countryside to be revitalized. It is of great practical significance in promoting China’s accurate poverty alleviation strategy, ensuring national food safety, promoting economic and social development, and strengthening the construction of ecological civilization.

2 Natural general situation and cultivation conditions

Hunan Province is located in the middle reaches of the Yangtze River, at longitude 108°47′to 114°15′east. It has a continental subtropical monsoon humid climate, Hunan has 1 300-1 800 h annual sunshine, and Hunan is rich in heat.

The average annual temperature is between 15 ℃ and 18 ℃, the frost-free period is 260 to 310 d, and the annual average precipitation is between 1 200 and 1 700 mm. The growth temperature range ofG.jasminoidesEllis is 10 ℃ to 35 ℃, and the optimum temperature is 20 ℃ to 28 ℃. It can be cultivated in well-drained hills, slopes, forest edge, front and back houses,etc., or sparse shrub land under the forest. The condition of planting soil can meet the standard of GB15618 II or above. The water quality for irrigation should meet the standard of GB5084 II or above.

3 Nursery site selection and preparation

3.1 Land selection and preparationThe plots with convenient transportation, adequate water source, good drainage, no pollution source, good light and aeration, flat terrain, deep soil layer and good permeability were selected as seedling nursery. In winter, quicklime (1 000-1 500 kg/667 m2) was spread evenly, and then 30-50 cm soil was ploughed deeply, and the soil was dried in the sun to improve the physical and chemical properties of the soil and reduce the source of overwintering insects.

3.2 Seedbed preparationOne week before sowing or cutting, the soil was raked flat, and the seedbed was made according to the terrain. The seedbed was 15-30 cm high, 100-150 cm wide and pathway was 40-50 cm wide. After the seedbed was finished, perlite (600-1 000 kg/667 m2) and rotten organic fertilizer (500-1 500 kg/667 m2) were evenly sprinkled, and the bed surface was raked and flattened. Before sowing or cutting, 1∶600-1∶800 carbendazol or 1%-3% FeSO4·7H2O solution was sprayed on the bed surface.

4 Seedling breeding

4.1 Seed collection and preservationFrom November to December, full, orange-red mature fruits without diseases and pests were collected from 3-10-year-old seedling seed tree with strong, no diseases and pests, full buds and big red fruits, and they can be sown as they were picked, or dried in a ventilated place with shells, sealed in cotton bags or net bags, and hung and stored in a dry and ventilated place indoors.

4.2 Seed treatmentBefore sowing, the fruit was shelled, soaked in warm water at about 40 ℃, rubbed to remove impurities, and repeatedly scrubbed with detergent until the water for washing was light yellow or nearly colorless. The sunken full seeds were taken out and drained, then soaked in 0.1% KMnO4solution for about 30 min, and then sown after being taken out and drained.

4.3 Sowing methodBefore or after rainy days from late February to April or late September to October, according to the sowing amount of 2-3 kg/667 m2, it was sown directly or sown in shallow furrows with a row spacing of 15-25 cm and a depth of 3-5 cm. After sowing, 1-3 cm of sifted yellow soil was covered, and then rice straw or rice husk was covered on the seedbed, and water was sprinkled to keep the soil moist.

5 Cutting propagation

5.1 Selection and treatment of cuttingThe healthy, pest-free and semi-lignified branches on the sunny side of the middle and upper part of the crown of the seed tree were selected. Cuttings were collected in the morning and evening of rainy or sunny days. After the cuttings were harvested, they were soaked and moisturized in water, and cut into 8-15 cm cutting slips with a flat upper end and a horseshoe-shaped cut at the lower end. The basal leaves of the stem segments were removed and 1-3 leaves in the middle and upper parts were retained. After pruning, the cuttings were arranged and tied neatly and soaked in 0.1% KMnO4solution about 10 min. After that, the base of the cuttings was quickly dipped in ABT or GGR rooting agent 10-20 s with the concentration of 500-1 000 mg/L.

5.2 CuttageThe cutting time is from March to May. The cutting plant spacing is 5-10 cm, and the row spacing is 10-15 cm. Before cutting, the seedbed was used as an arch shed, and the hole was dug first before cutting. The cuttings were buried at the depth of 1/2 and 2/3 of the base, and the soil at the base of cuttings was compacted and watered thoroughly. The arch shed was covered with transparent film to keep the temperature and humidity in the shed and bed surface.

6 Seedling stage management

6.1 Moisture and temperature managementIt was properly watered to keep the seedbed and cuttings moist. Stagnant water should be removed in time after rainfall.

In the 30-50 d after sowing or cutting, when the air temperature is ≥ 28 ℃, the sun shading net should be covered and water should be sprinkled to cool down.

6.2 Seedling bed sterilizationEvery 10-15 d after sowing or cutting, 1∶600-1∶800 carbendazol or 0.1% KMnO4solution was sprayed once.

6.3 Cover removalAfter sowing for 40-50 d, the sprouts had 2 leaves and 1 heart, the covering grass could be removed, and it is advisable to carry out on cloudy days.

After cutting for 40-60 d, the seedlings took root neatly, and the film at both ends of the arch shed could be opened for ventilation, and the film was gradually removed after 1 w.

6.4 Loosening soil, weeding and thinningIt should be loosened and weeded in time; generally every 15-20 d, it should be uprooted after rain or irrigation.

The seedlings were thinned out at different stages, and the seedlings with imperfect development, injury and infection of diseases and pests were pulled out in time, so that the seedlings were evenly distributed in the seedling bed, and the general plant spacing was 5-8 cm.

6.5 FertilizationAfter setting the seedlings, we began to fertilize properly, mainly with nitrogen fertilizer, supplemented by phosphorus fertilizer, using a small amount for many times. From May to July, 0.1% water-soluble compound fertilizer solution or 0.1%-0.2% urea solution was sprayed on leaf surface every 15-20 d. From August to September, 0.2%-0.3% urea solution and 0.2%-0.5% KH2PO4solution were sprayed for 3-5 times. The use of fertilizer shall be carried out in accordance with the regulations of NY/T394.

7 Land preparation and afforestation

7.1 Selection and planning of afforestation sitesLoose and fertile suitable forest land with sufficient sunshine, good drainage and no pollution source, hilly gentle slope land or sporadic plots along the edge of forest or in front of and behind houses were selected as afforestation sites. The main contents and requirements of afforestation planning and design shall be carried out in accordance with the provisions of GBT15776-2016.

7.2 Land preparationFull reclamation or block land preparation was adopted when the slope was below 5°. When the slope was between 5°and 20°, the soil was prepared in a belt along the reverse slope of the contour line, which was low in the inside and high in the outside. Generally, the outer height is 10 cm and the width is 1-3 m, which is beneficial to water storage and soil conservation.

8 Planting

8.1 Selection and treatment of seedlingsThe seedlings with stem height of more than 30 cm, developed root system, no diseases and pests, robust growth and consistent flowering period were selected. When lifting seedlings, we should water them thoroughly, dig them with a hoe, and do not pull up seedlings with hands. Generally, the seedlings should be planted as they are lifted, if we fail to do so, the seedlings should be bundled by different grades after they are dug up, and the seedlings should be transported away on the same day. After arriving at the destination, the seedlings should be planted in the cool place on the leeward side and planted as soon as possible.

Before transplanting, the tender shoots of the seedlings were cut off, and the seedlings were fully mixed with rooting powder and yellow mud according to the proportion of 1∶10, and then mixed into a paste for the root to be dipped in, which could effectively shorten the slow seedling period.

8.2 Transplanting timeFrom February to May or from November to December, it is appropriate to transplant before rainy days or in cloudy or light rain weather.

8.3 Planting requirementsThe plant spacing is about 1.5 m, the row spacing is 1.5-2.0 m, and the planting density is (200-300) plants/667 m2. It can be sparse for interplanting, and it can be dense when interplanting is not feasible.

The hole was dug at a fixed point, and the specification of the hole was set according to length of 50 cm, width of 50 cm and depth of 40 cm. The hole was treated with 1.0-2.5 kg rotten organic fertilizer, backfilled with topsoil and evenly mixed with fertilizer. A strong seedling was planted in each hole, the seedling was straightened and planted in holes. After loosening the soil and backfilling, the seedlings were lifted up when they were half filled, so that the roots were stretched and compacted, and then the soil was added until the hole was full, and it was compacted with feet. The planting depth should be 2-3 cm slightly higher than the soil mark position of the seedling stem out of the nursery.

9 Nurturing management

9.1 Intertillage and weedingOne year to three years after planting, weeding was carried out once in spring, summer and autumn, respectively. After that, weeding was carried out timely according to the growth of weeds in the woodland. It was completely reclaimed and cultivated in winter.

9.2 Fertilization(20-25) kg/667 m2compound fertilizer or (1 000-1 500) kg/667 m2decomposed farm manure was applied every winter or from January to February of the following year. In spring and summer, 10-15 g compound fertilizer was applied per plant to promote branching and bud formation, which was beneficial to the formation of reasonable tree structure.

9.3 Interplanting and underforest cultivationBefore closing, legume crops such as peanuts and soybeans, green-mature crops or other dwarf crops can be interplanted. After interplanted crops were harvested, the straw was buried in the soil. After the forest was closed, poultry such as chickens, ducks and bees can be raised under the forest. While improving the soil, it can improve the economic benefit.

9.4 Flower and fruit managementAt the early flowering stage, it is appropriate to release bees under the forest with a beehive for 1 333.3 m2of land. Insect vectors were used to promote pollination, and flowers can be used as raw materials for cooking or extracting essential oils 1-2 d after blooming, playing a role in thinning flowers and controlling fruits, so as to achieve the dual-use purpose of flowers and fruits. In full bloom, 0.15% borax+0.2% KH2PO4was sprayed on the leaves in cloudy days or in the evening to increase the fruit setting rate. The fruit expansion and development period ofG.jasminoidesEllis was from June to October. 0.25 kg N, P and K compound fertilizers were applied once per plant in late June and early August to promote fruit development. After fruit harvest from late October to late November, (1 500-2 000) kg/667 m2mature farm fertilizer and 100 kg/667 m2calcium magnesium phosphate fertilizer were applied to restore tree vigor, promote flower bud differentiation and improve the ability of trees to survive the winter.

9.5 Trimming and pruningAfter planting, the trunk was cut off the young tree at 20-25 cm from the ground. When the summer shoot was about 20 cm, 3-4 healthy, pest-free and stout branches were evenly selected as the main branches in different directions of each plant. In the second year, when the summer shoots sprouted, three or four robust and evenly distributed accessory branches were cultivated on each main branch, and after two or three years of pruning and shaping, the crown was gradually cultivated into a round head shape. Within 2 years of planting, weak and diseased branches, water sprouts, and long branches should be cut off in time to facilitate the growth of young trees and crown cultivation. In order to facilitate harvesting, the height ofG.jasminoidesEllis is generally controlled at about 2.0 m.

10 Pest control

It is necessary to adhere to the principle of "prevention first and comprehensive control", carry out monitoring and investigation of forestry pests, and take comprehensive measures dominated by biological control, supplemented by physical control and chemical control to carry out prevention or pollution-free control measures. Chemical pesticides are prohibited 45 d before fruit harvest to ensure the quality and safety of the products. The prevention and control of diseases and pests should follow the regulations of GB4285 and NY/T1276.

The main diseases and pests ofG.jasminoidesEllis include brown spot, chlorosis, leaf borer, Cephonodes hylas, aphids, scale insects and so on. The main control methods of diseases and pests are as follows: (i) Brown spot. It infects the leaves and fruits ofG.jasminoidesEllis. In serious cases, it can lead to leaf shedding, early fruit drop and affect the yield. The main onset period is late May and early August. By strengthening pruning, burning diseased plants, diseased leaves, and later tending and management, we can prevent the spread and transmission of the disease, promote the exuberance of the tree, and enhance the disease resistance. From May to August, 1∶100 Bordeaux mixture was sprayed every half month for protection and prevention. The disease can be prevented and treated with high-efficiency and low-toxic fungicides such as Tuzet, and Thiophanate-methyl. (ii) Chlorosis. It is mainly caused by the lack of iron, magnesium and fertilizer in plants. First of all, it occurs on the tender leaves at the end of the branch, and green color fades from the edge of the leaf, developing to the center and gradually aggravating, until the leaf turns yellow, and finally the leaves perished and dried up. Control method: It can be planted in well-drained, soft and fertile acid soil. Organic fertilizer made by mixing ferrous acid and zinc sulfate can be applied. At the initial stage of the disease, the diseased plants can be irrigated with 2%-3% FeSO4·7H2O, or 0.1%-0.2% FeSO4·7H2O can be sprayed on leaves. The treatment of chlorosis with drugs should be carried out at the initial stage of the disease, otherwise the effect is poor.(iii) Leaf borer. Its larvae bite the bud leaves and tender leaves of branch tips and roll the leaf buds into bracts. Overwintering pupae can be reduced by reclaiming the garden in winter. When it occurs in June and September, chemical pesticides with high efficiency, low toxicity and low residue (including 90% 1∶1 000 trichlorfon or 20% 1∶2 000 Fenvalerate) can be sprayed. (iv) Cephonodes hylas. The larvae nibble on the leaves, and the fifth instar larvae eat too much. In a year, the mature larvae can enter into the soil and pupate to survive the winter. It can be killed by biological pesticide spray such as 1∶100 Bacillus cereus solution (containing more than 10 billion live spores per gram). (v) Aphids and scale insects. They can do damage to top buds, shoots, tender stems and leaves. They can be controlled with 10% 1∶1 000 Buprofezin or 1∶10 rosin mixture or sprayed with lime sulfur when clearing the garden.