Study On The Occurrence And Causes Of The " Reflorescence" Of Pear In Fujian Province

Pyrus pyrifolia Nakai is the main cultivar of pear in Fujian province, its producing areas are mainly concentrated in the mountainous areas of the northwest of Fujian Province, which is in the southern tip of the pear producing area in China. Because of its special geographical position, Fujian Province has the unique advantage of developing Pyrus pyrifolia Nakai, which is the main production area of China’s Pyrus pyrifolia Nakai. Pyrus pyrifolia Nakai leaves in autumn and winter which is formed in the long process of life to cope with adversity self-protection physiological responses just likes other deciduous woody tree. With global warming, extensive management and other reasons, the phenomenon of early defoliation in the producing areas have different degrees of occurrence, and often accompanied by the occurrence of reflorescence. The phenomenon is wider range, greater harm, especially in Pyrus pyrifolia Nakai producing areas in the south of the Yangtze River Basin provinces (city, district).This paper mainly carries an investigation on the phenomenon of early defoliation and reflorescence in multiple pear orchards in Jianning County of Fujian Province currently. Based on the investigation results and the theoretical research, it’s the first time to use’Pyrus pyrifoliavar.Huanghua’as experimental materials for an outdoor control cultivation of reflorescence and delayed leaf falling test, from the two aspects of the prevention and application of reflorescence. Hope to provide some help in preventing pear reflorescence and getting in-depth understanding of the reflorescence’s mechanism, and exploring the feasibility of artificial control on pear reflorescence. The main conclusions of this paper are as follows:1. The situation investigation about reflorescence of pear in Jianning county of Fujian Province:climatic factors, ecological discomfort, genetic background, improper management and so on, which all have some influence on the occurrence of early deciduous leaves and reflorescence of South Pyrus pyrifolia Naka. But the research in pear orchards of Jianning county inclined to that the leaf disease is the main cause. Due to different terrain, elevation slope section, rain shelter and open field cultivation, grafting ratio, fertilizer and water management level, there is a significant difference in reflorescence of pear. Because these factors can affect the site conditions, temperature, humidity, tree vigor, dissemination of disease of difficulty degree which may inhibit or aggravate the effect to the disease. Therefore, leaf disease is a major cause of reflorescence occurred in Jianning county.2. Postharvest defoliation control in reflorescence research of pear in Fujian, the result showed that:(1) The postharvest defoliation forcing effect is obvious. The whole leaf treated pear trees sprout rate is more than 60% on average. This verified the direct reason of early defoliation is that "Indian summer" weather contributed to the occurrence of pear’s reflorescence.(2) Different postharvest defoliation methods induce different effect of pear reflorescence and reviving. The whole defoliation pruning of forcing effect is the best, its germination rate is above 60%. Artificial whip half of defoliation pear’s germination average rate is about 40%. Lime sulfur of defoliation pear’s germination rate is between 10-20%. This shows that whole defoliation is the key to the occurrence of reflorescence(3) From the forcing effect of two processing period, Treated pear’s germination rate on August 20 is slightly higher than that on August 31, the difference between the two germination rates is less than 10%. It suggests that postharvest defoliation treatment is earlier, the effect is more obvious.3. Postharvest delay defoliation prevention in reflorescence research of pear in Fujian:postharvest spraying plant cytokinin (CTK2) and clopidogrel benzene urea (large fruit Shi Premium) of pear trees can effectively reduce the defoliation rate of 10-25% in late September to mid-November. However, brassinolide and foliar fertilizer (oasis god dew) exacerbate the defoliation, especially the pear tree spraying the oasis god dew, when compared to natural pear tree defoliation rate which is increased by 23.73% on October 9. Other reagents such as gibberellin, curse, the import growth refined (Biyang Kunlun Biological Technology Co., Ltd.) and so on have little effect. Because the contrasted pear trees have no phenomenon of early defoliation and reflorescence, some reagents in a certain period reduced the leaves, but the defoliation of the delay effect was not obvious, the processing pear trees and control pear trees’germination rate are both zero.