Effect Of Fertilizer Application And Fruit Thinning On Fruit Yield And Quality Of Chaenomeles Speciosa (Sweet) Nakai

Chaenomeles speciosa（Sweet）Nakai（C.speciosa）is known as the"fruit of a hundred benefits",with high medicinal and edible value,is a valuable fruit with significant development value.At present,with the rapid development of C.speciosa processing industry,has developed a C.speciosa fruit drink,dried fruit and other edible products.In addition,C.speciosa health products also have great market potential.Therefore,the market demand for C.speciosa fruit is greatly increased,and there are higher requirements for the quality of the fruit.Improving the yield and quality of fruits in cultivation is the core of improving market competitiveness.In this study,we investigated the effects of three cultivation measures,namely nitrogen,phosphorus and potassium fertilization,foliar spraying of calcium,magnesium and boron fertilizers and fruit thinning,on the yield and quality of C.speciosa fruits using Chaenomeles speciosa（Thouin）Koehne’Changjun’as the test material.The best cultivation scheme for high quality and high yield of C.speciosa was obtained through a comprehensive comparison of various analytical methods such as ANOVA,Correlation Analysis,Range Analysis and Principal Component Analysis,and the results of the experiment are as follows:（1）Different levels of N（100、200、300）、P（40、80、120）、K（80、160、240）treatments were able to increase fruit yield and improve fruit quality in different degrees.The19 fruit indicators of C.speciosa were analyzed by principal component analysis,and the scores of different treatments were ranked from 5（N₂P₂K₃）>4（N₂P₁K₂）>6（N₂P₃K₁）>2（N₁P₂K₂）>9（N₃P₃K₂）>8（N₃P₂K₁）>7（N₃P₁K₃）>1（N₁P₁K₁）>3（N₁P₃K₃）>CK（N₀P₀K₀）.The overall scores of all treatments were higher than those of CK,and treatment 5（N₂P₂K₃）had the highest overall score,It had the best overall effect on fruit quality and yield of C.speciosa.（2）Using ¹⁵N and ¹³C isotope tracing techniques,we labeled whole C.speciosa plants under different N,P and K treatments during the fruiting season to study the translocation and distribution of carbon and N assimilation products,and investigated the changes of soil and photosynthetic indexes under different N,P and K treatments.The results showed that the appropriate level of nitrogen,phosphorus and potassium fertilizer could improve soil conditions,increase N utilization,improve photosynthetic efficiency of leaves,promote the synthesis of carbon and nitrogen assimilation products,promote more efficient transfer of assimilation products to fruits,and increase fruit biomass.Both ANOVA and Range Analysis results indicated that treatment 5（N₂P₂K₃）had the best effect.Combining the results of the two experiments in（1）（2）,treatment 5,i.e.435 g urea,444g calcium superphosphate and 462 g potassium sulfate per tree,was recommended for fertilization in actual C.speciosa production.（3）Foliar sprays of different concentrations of calcium（C:0.1%、0.2%、0.3%）,magnesium（M:0.5%、1.0%、1.5%）and boron（B:0.1%、0.2%、0.3%）fertilizers improved fruit yield and quality of C.speciosa to varying degrees compared to the water treatment.Among them,treatment M1 had the best effect in improving yield and treatment B3 had the best effect in improving quality.The overall scores of the principal component analysis for each treatment were ranked from highest to lowest as B3>M1>C2>C3>B1>M3>B2>M2>C1>CK,with B3,M1 and C2 having the highest overall scores.Therefore,the optimal concentrations of the three fertilizers for foliar spraying were 0.3%Borax,0.5%Mg SO₄,and0.2%Ca Cl₂.（4）Using the optimal concentrations of calcium,magnesium and boron fertilizers derived from result（3）,the foliar application of calcium,magnesium and boron fertilizers alone and in combination in the second year on C.speciosa,different treatments were able to improve fruit yield and quality of C.speciosa to different degrees.The results of principal component analysis showed that the effect of each treatment on yield and quality of papaya was ranked from best to worst as Ca+Mg+B>Mg+B>Ca+B>Mg>Ca+Mg>Ca>B>CK.Treatment Ca+Mg+B had the highest overall score.Therefore,considering the yield and quality factors,the triple fertilization of 0.2%Ca Cl₂,0.5%Mg SO₄,and 0.3%borax solution fertilizer was the most effective during the fruit development of C.speciosa.（5）After fruit thinning at the beginning of fruit growth,different levels of fruit retention can affect fruit yield and quality of wrinkled papaya to different degrees.The scores of principal component analysis of each treatment were ranked as T6>T5>T7>T3>T4>T8>T2>CK>T1,with the highest overall score for treatment T6,followed by T5 and T7.Therefore,in the actual fruit thinning work,the fruit retention amount can be controlled from T5 to T6,i.e.50-70 fruits/plant.This fruit retention amount can maximize the yield,ensure the quality and increase the economic benefits.