Study On The Causes And Prevention Of Pan Jujube Fruit Shrinkage Disease

Following with the continuous downturn in the price of dried jujube in Xinjiang,improving grafted fresh jujube has gradually become a new way for jujube farmers to improve planting efficiency.As an excellent fresh food variety with early maturity,large fruit,crisp taste and high soluble solids content,Pan jujube has become a new favorite in the market and has begun to be rapidly promoted in Xinjiang.At present,about 20,000 mu has been planted in Xinjiang.However,in the process of cultivation and production,it is found that Pan jujube fruit is prone to fruit shrinkage,which will cause a significant decrease in fruit commodity rate and seriously affect planting efficiency.It is urgent to solve the problem of Pan jujube fruit shrinkage.In this study,the high-grafted Pan jujube on Junzao in the standardized production base of Pan jujube in Yangtake Township,Maigaiti County,Kashgar was used as the experimental material.Through the spatial distribution of Pan jujube fruit,branch group type,mineral nutrition,pesticide control effect and other channels,in order to explore the cause of Xinjiang Pan jujube fruit shrink disease,find out the law of disease and control methods.The findings are as follows :(1)The spatial distribution of jujube fruit shrinkage disease was mainly concentrated in the upper canopy with the longest exposure time to light,and the difference between the upper canopy and the lower canopy was the largest,with a difference of 10.45 %.Compared with the fruit on the shedding jujube hanging,the fruit shrinkage rate of the former was 39.9 % higher than that of the latter.With the same lignification jujube hanging fruit,the fruit shrinkage rate of 2a branch lignification jujube hanging fruit was nearly 2 times higher than that of 1a branch lignification jujube hanging fruit.The fruit shrinkage rate of jujube hanging on 2-year-old branches was nearly 3 times that of 1-year-old branches.(2)The fruit shrinkage rate of Pan jujube increased with the increase of fruit number,and the higher the yield per plant,the higher the fruit shrinkage rate.When the number of jujube hanging fruit is5-6,the increase rate of fruit shrinkage rate decreases.(3)Pan jujube fruit shrink disease is susceptible to weather,temperature and humidity.The average daily temperature was 25.26℃ and the average humidity was 38.80 %.In contrast,the daily average temperature is higher and the air humidity is lower.(4)It was found by paraffin section observation that there was a significant difference in the content of cavity in fruit cells between healthy and diseased fruits.Among them,the cavity of the diseased fruit accounts for a large proportion,the cuticle and epidermal cells are broken,and the pigment distribution is uneven with yellow green,dark green,rusty and reddish brown.However,the cavity inside the healthy fruit was less,the epidermal cells were closely arranged,and the color distribution was uniform without obvious pigment precipitation.The cuticle and epidermis of healthy fruits were thicker than those of diseased fruits.The cuticle of healthy fruits was 0.66-1.27 μm thicker than that of diseased fruits in each period,and the epidermis was 4.71-7.07 μm thicker than that of diseased fruits.(5)After potassium humate fertilization treatment.The contents of B and K in fruits,stems and leaves of Pan jujube were significantly higher than those in the control group.Therefore,the lack of B and K elements will cause the occurrence of Pan jujube fruit shrink disease;Zn element has a certain influence on the fruit shrink disease of Pan jujube,but the specific influence degree needs further study.The content of Mg and Ca had no obvious effect on the occurrence of fruit shrink disease.(6)Tetramycin had the best control effect on jujube fruit shrink disease.Tetramycin is a fungicide for the prevention and treatment of bacterial infection.Therefore,it can be speculated that bacterial infection may also be one of the causes of jujube fruit shrink disease.