Study On Biotechnology To Prevent The Wizened Bud Formation Based On Comparison Of Wizened Bud And Normal Bud In Pear

In recent years,there are more and more reports about the huge economic losses in production caused by pear wizened bud.Wizened bud is a phenomenon due to the discordant between internal growth and external environment of flower bud that lead to adverse flower bud differentiation.In order to solve the industrial problem,firstly,this study has conducted an investigation and statistics on the occurrence rate of wizened bud,and researched the effects of leaves nutritional status,soil conditions and meteorological factors on wizened bud formation of pears which have differentr wizened bud rates.We then analyzed physicochemical properties and differentially expressed genes between wizened bud and normal bud.Finally,according to the above research,this paper put forward some technical measures to solve the phenomenon of wizened bud.The main research results are as follows:1.The study has conducted an investigation on wizened bud rate of six pear cultivars at Jiangpu horticulture pear germplasm garden of Nanjing Agricultural University,Horticulture Reseach Institute of Henan Academy of Agricultural Sciences,Shijiazhuang Pomology Institute of Hebei Academy of Agricultural and Forestry Sciences,a pear orchard of Xinji city Hebei province,a pear orchard of Yufa town Daxing district Beijing,a pear orchard of Qinglong county Hebei province and Pomology Institute of Shanxi Academy of Agricultural Sciences during germination stage in 2015.The occurrence rate of different pear varieties at the same area showed significant difference.The high occurrence rate of wizened bud of pear cultivars at Nanjing,Zhengzhou and Shijiazhuang were'Niitaka','Yuluxiang','Jiyu'.For the widely cultivated 'Yuluxiang',the occurrence rate of wizened bud were not consistent.Zhengzhou was the most serious,followed by Beijing and Xinji,Qinglong county and Taigu county had no wizened bud phenomenon.2.The study selected the widely cultivated and wizened bud susceptible cultivars'Yuluxiang' at Horticulture Reseach Institute of Henan Academy of Agricultural Sciences,a pear orchard of Xinji city Hebei province,a pear orchard of Qinglong county Hebei province and Pomology Institute of Shanxi Academy of Agricultural Sciences and analyzed their leaves nutritional status,soil condition and climatic characteristics.Research results showed that leaves and soil had more abundant calcium content and boron content at the places which have a high occurrence rate of wizened bud.And the environmental conditions of high temperature and high humidity hindered the transport of this two elements to the flower bud.Thus,the imbalance of vegetative growth and reproductive growth promoted the formation of wizened buds.3.The study selected 'Niitaka' with the highest wizened bud rate at Jiangpu horticulture pear germplasm garden of Nanjing Agricultural University as test material,and measured mineral elements,endogenous hormones,POD activity,SOD activity and free proline between wizened bud and normal bud.This study showed that phosphorus,potassium,zinc,boron element content was significantly higher in normal buds than that in wizened buds during germination,and calcium element content showed the opposite.Normal flower bud contained lower level of ABA content,but the content of IAA,GA3 and ZT was relatively high.In addition,the higher activity of POD,SOD and the free proline content in normal buds were significantly higher than that in wizened buds.Thus,pear flower bud germination were regulated by various hormones,mineral elements,related enzymes and free proline,but these indicators of wizened buds showed abnormal,so wizened buds couldn't germinate.4.The study selected the most serious pear varieties 'Yuluxiang' at Horticulture Reseach Institute of Henan Academy of Agricultural Sciences and collected wizened buds and normal buds at about 10 days before flower bud germination.In this work,POD activity and ABA content were higher in wizened buds,but SOD activity and the contents of IAA,GA3 and ZT were lower in wizened buds.By RNA-Seq technology,the differential expression genes between wizened bud and normal bud were significantly enriched in the classification of "oxidoreductase activity" and participated in the plant hormone signal transduction pathway.The discovery of these genes provides a clue to further revealed the occurrence of pear wizened bud from the perspective of molecular biology.5.The study selected 'Yuluxiang' with the highest wizened bud rate at a pear orchard of Yufa town Daxing district Beijing as test material.In the stage of flower bud differentiation,boron fertilizer,calcium fertilizer,zinc fertilizer and exogenous hormones(IAA,GA3,6-BA)were sprayed with different combinations.Then we count the wizened bud occurrence rate of each treatment next year.Taking into account the results of the study,the cost and the effect of the growth regulator on the tree,we suggested that in the early stage of flower bud differentiation,spraying once 0.2%boron fertilizer to reduce wizened buds.It provided the technical reference for the effective prevention of wizened buds.