Causes and Control measures of low Fruit setting rate of soft seed Pomegranate in Qianxi County, South China

Causes and Control measures of low Fruit setting rate of soft seed Pomegranate in Qianxi County, South China

1 Development status of soft seed pomegranate in Qianxi County

At the beginning of 2008, Longxing Ecological Farmers' planting Professional Cooperative of Zhongping Town, Qianxi County, Guizhou Province introduced 100000 Tunisian soft-seed pomegranates from Wuhan, Hubei Province, for trial planting in Guanzhai Village, Zhongping Town, and began to hang fruit in 2010. After nearly 5 years of observation and comparison, under the influence of climate and soil in Qianxi County, the fruit quality of this variety is good, and its color and flavor are different from those of other planting areas, so it is well received by consumers. At the beginning of 2013, Qianxi County named its fresh fruit Shuixi ruby soft seed pomegranate, registered its trademark, and developed Shuixi ruby soft seed pomegranate as an important fruit tree variety for precise poverty alleviation. By the spring of 2013, 3 836.8 hm2 of Shuixi ruby soft seed pomegranate had been planted in the county, of which 126.7 hm2 planted from 2008 to 2012 had entered the full fruit stage, and 3 510.7 hm2 planted from 2017 to 2015 had entered or will enter the full fruit stage.

Due to less sunshine and abundant rainfall, soft-seed pomegranate in Qianxi County has exuberant vegetative growth, large branch and leaf growth and strong growth potential, but the proportion of well-developed complete flowers is small and the fruit setting rate is low. The enthusiasm of growers to develop soft-seed pomegranate has been greatly affected. Solving this problem is the key to promote the sustainable development of soft-seed pomegranate industry in Qianxi County.

2 the reasons for the low fruit setting rate of soft seed pomegranate in Qianxi County.

Rain Water's abundant soft-seed pomegranate is a light-loving plant. High temperature and drought weather is beneficial to flower bud differentiation, and the proportion of complete flowers is more. On the other hand, the lack of light and the overcast and rainy weather of Rain Water will cause the plant vegetative growth to be too prosperous, resulting in a serious imbalance between vegetative growth and reproductive growth, pistil degeneration of pomegranate flowers, few well-developed complete flowers and fall off immediately after flowering. This phenomenon is very prominent in the head stubble flowers. The effective flowering period (first stubble flower and second stubble flower) of soft seed pomegranate in Qianxi county is from the beginning of May to the first and middle of June. During this period, it is low temperature and rainy all the year round in Qianxi county, the activity of insects in continuous low temperature, overcast and rainy weather decreases, and pomegranate pollination is affected. At the same time, when Rain Water was immersed in the flowers, the pollen could not be pollinated normally or incompletely under the influence of Rain Water, resulting in a large number of falling flowers and fruits.

2.2 extensive management due to the fact that most of the rural young and middle-aged labor force go out to work, the rural labor force at home is dominated by women and frail or older male workers, and the unreasonable labor structure hinders the development of the pomegranate industry to a certain extent. The main results are as follows: (1) the quality of the labor force of home farming is low and lack of scientific and technological awareness. Although the government has carried out training on pomegranate cultivation techniques in relevant townships (towns) for industrial development, due to the low quality of the labor force, the trainees cannot understand the contents of the training. the cultivation techniques to improve the fruit setting rate of pomegranate, such as branch pulling, ring cutting, sprouting, flower and fruit thinning, fertilization and pest control, have not been used in production practice, and the pomegranate planted by farmers still does not care. (2) A large number of rural labor force go out to work, resulting in an increase in the input cost of rural labor force. In order to save costs, pomegranate planting enterprises, cooperatives and large growers can only adopt extensive management model [Jishan Huayao].

3 measures to improve the fruit setting rate of soft seed pomegranate in Qianxi County

3.1 suitable for tree pomegranate planting land, choose sandy loam or loam with sufficient light.

3.2 artificial shelter from rain during flowering period, trees were used to cover the white agricultural film to prevent Rain Water from entering the flowers.

3.3 artificial pollination uses artificial pollination to reduce the problem of non-pollination or incomplete pollination caused by the lack of insect activity in the rainy season.

3.4 reasonable pruning

3.4.1 pull branches pull the main branches, lateral branches and fruit branches of pomegranate into a flat oblique shape, the reasons are as follows: (1) to control the vegetative growth of pomegranate and promote the reproductive growth of pomegranate; (2) after pulling the branches into a flat oblique shape, the pomegranate flower is also inclined, which can prevent a large number of Rain Water from entering the flower to affect pollination and fertilization.

3.4.2 girdling peeled trees, branches and trees that did not blossom and bear fruit on time. The girdling time was 5 months (controlling vegetative growth and increasing fruit setting rate) and 7 months (promoting flower bud differentiation). The girdling width was 1 / 10 of the circumference of the trunk. Immediately after the ring peeling, bandage the wound with an old newspaper.

3.4.3 when the tree is in blossom, it will trench and cut the root at the base of the tree to control its vegetative growth and promote reproductive growth.

3.4.4 remove sprouting and thinning branches and remove the sprouting tillers on the root neck and trunk in time, and remove overgrown, weak and dense branches as soon as possible.

According to the characteristics of abundant Rain Water and vigorous vegetative growth of soft seed pomegranate in Qianxi County, fertilization is mainly based on fully mature organic fertilizer and phosphorus and potassium fertilizer, combined with foliar fertilizer to reduce the amount of nitrogen fertilizer. The base fertilizer was applied from September to October, no more than November at the latest. The varieties were mainly muscle fertilizer, and proper amount of potassium sulfate compound fertilizer was added. Sprouting fertilizer is applied before budding, and the variety is organic fertilizer; pre-flowering fertilizer is applied before flowering, and the variety is compound fertilizer with high phosphorus content; foliar fertilizer is sprayed with 0.3% ~ 0.5% potassium dihydrogen phosphate at early flowering stage, and 0.2% ~ 0.3% borax solution is sprayed at full flowering stage.

3.6 after flower thinning and fruit budding, complete flowers and incomplete flowers can be identified, incomplete flowers can be thinned every 7 ~ 10 days, and flowers after 3 and 3 crops of flowers can be removed in time. After the end of physiological fruit drop, one or two fruits are left in each inflorescence, and malformed fruits and diseased fruits are removed in the young fruit stage.